How to weigh different aspects?

Well, you aren't alone.  I'm pretty sure everyone struggles with this, as it is the eternal dilemma of all traders.  And today was a bit tricky indeed.  This is the mindset I have been working on:

a) how do the best swings start.  one example is a micro DB/DT FBO at the open -- that is what b4 is, a mDT with 1 and FBO of GXH/HOY.  but not just the pattern but how do the bars look.  Notice b4 did close well below b1 low, it didn't test the b1 low and then put a conspicuous lower wick on b4 for example.  b2/3 are ii so BOM, and b4 failed above and broke out strongly below, so I think the mindset at that point should be bears getting a 2nd leg, so I ignore taking the b5 buy signal because of that.  It is a bit different than yday (8/21) b9 where we had a 3 push up, and a vacuum to the bottom of the leg, so big up and big down, can be DB there and continue in TR.

b) once you are confident of what swing the market is on (i.e. should be able to say things like, "we are on the short below 4"), then you look for flags in that direction, or a very good reversal setup.  So the 4th arrow (the 2nd buy arrow for b11), I see a possible wedge, but that's if you count the transition leg (b1) which isn't as reliable, and the b6-9 leg was fairly strong and may also want another leg.  Then, b9-11 have nearly 100% overlapping bars so that is a warning sign as well.  You should already be considering waiting for a second signal due to the bear strength, and then the first signal doesn't even look that great with the overlap.  b17 looks like a possible wedge buy (b9/13/16) and you are expecting minimum of 2 legs, but we did get a brief 2 legs and a strong bear bar again, so you need to exit long below 20 and consider selling 20 as well as some kind of bear flag (like a DT bear flag b12/19) -- it went mostly sideways into the EMA and then a good bear bar so that is a bear flag in the direction of the likely current swing ('on the sell below 4').  When would it have switched to 'on the buy above 20', well i would say if it didn't fail in a few bars that might have been the start of a new major swing (or at least a swing that gives you good opportunity to escape when it fails).

Other notes per your comments:

-technically we did get a 2nd leg up from the gap up but a very minor one, b2/3 pause and 4 up.  But in any case, as you noticed with putting quotes on "need", you don't really need a 2nd leg up.

-we failed twice to produce a strong BO above HOY, so I would not think of it as support anymore.  b1 couldnt get FT on b2, making a bear bar COL, then b4 strong bear close below HOY.  So is more of a FBO HOY than finding support at HOY.  Same with GXH, we FBO above so it is not support -- in fact b5 re-test it and make another bear b6.

-look at a daily RTH chart, in this most recent bull leg, how many times did we tap HOY from above and then rip up? most of the bars have a fair amount of overlap.  So doesn't seem that likely we just come down and test HOY and go into a big bull trend

-we were on a 13 bar bull MC on the daily RTH chart, this is a record from what I can tell (at least in the last 27 years).  So we set a record MC, then gap-up above HOY today (late in the trend), this can be climactic behavior and due for a pb.  The last 2 days were weak dojis as well.  It made sense to finally break the streak today then.  So it is never as simple as, we're bullish on the daily so we're just going to go up smoothly everyday.

Very insightful, thanks a lot!

About this point: Then, b9-11 have nearly 100% overlapping bars so that is a warning sign as well.

I know that a reversal bar has to reverse something, and when its a TTR there's nothing to reverse. So maybe that's what you mean with warning sign?

On the other hand, there are also numerous occasions where Al throws his own advice out of the window and takes these kinds of TTR entries on a first decent signal (H1L1). I think because you can also view the brief TTR as a brake on the steep trend, slowing the momentum of the bear trend and getting ready for a leg or two up. Apparently not in this case, but that's what I have to learn I guess. 

Same with this point btw: "So the 4th arrow (the 2nd buy arrow for b11), I see a possible wedge, but that's if you count the transition leg (b1) which isn't as reliable".

I see him using the opening bar a lot for drawing wedges, when it is convenient to him. But maybe its like you said, it can be a wedge, but its less reliable when you draw it this way. So it  depends on the entirety of the context. And therefore also very foggy to really discern the correct weighing of the situation. An eternal dilemma like you said 🙂 

Yes a dilemma indeed. If it is an ugly shaped wedge, then some other positive factors help-- like it testing a key area, a climactic reversal, etc.  Typically you either want weak bears or climactic bears for thinking of reversal-- steady selling typically want to wait for a bigger pattern.

Another idea is pattern completeness, if you are thinking spike and channel then don't take a reversal after a minor 2nd push, it can easily get 2 more push... unless it evolved to something else, like a cc climax for example.

Al I do think occasionally does markings/comments that are convenient to the chart, but hard to demand perfection when he is not a systematic trader.  If you look at many many EOD charts you will see he is mostly consistent, and sometimes there are subtleties you don't yet see -- this is often in how the bars look moreso than whether or not I use b1 to draw the wedge.

I always start the day by looking at the higher-timeframe context.  In this case we were at the top of a broad channel on the hourly chart:

This is also functionally a wedge, yesterday tagged the upper channel line almost to the tick and sold off.

The strength of the downside breakout was very surprising, but price pulled back and tested the broken trendline later in the session.

This is classic price action: a channel breakout, pullback, retest.  But if you're only looking at the 5 minute chart then you're oblivious to what's actually happening.  

One thing I missed recently was that we tagged the 16th July Low in the Cash index and closed the gap, so this was an additional reason for a sharp reversal from here:

The gap remains open on my Ninjatrader Futures Globex and Day session chart.  I don't know how much that matters if the cash index gap is closed.  I would guess the index is king but we may need to go up and close the futures gaps too.

Thank you both, I notice that I have to remember to constantly shift between all the layers of patterns and variables in my analysis. On every bar I should zoom out and look at the bigger picture, then zoom in at the swing level, leg level, and then bar level. And base my decision on the combination of all these levels. 
It easy to lose sight of the higher levels and focus only on the lower ones if you stare at a chart too long.