The thing is, I'm not too terribly interested for a few reasons.
The first being, in virtually every circumstance that I've had the option to throw out BT B+K, it's the only option aside from 50/50 mixups. Zasalamel WR K and Ivy SW 6A+B are examples of this. When I throw it out, it's not so much of a "I'm going to GI with this move" as it is a "Let's hope I get lucky" kind of situation. Suffice to say, without any kind of planning, it doesn't really matter knowing what verticals it will impact, since you are just plain guessing. And I think with BT B+K, that it's so gimmicky you have to be.
Not to mention, the idea of using these verticals against a back-turned opponent seems laughable. For example, what Yoshi in his right mind is going to use 6B on a back-turned Siegfried? There are plenty of better options at Yoshi's disposal, and if you've somehow played enough mindgames to force him to use 6B on you, you're probably the greatest theory fighter in the world. I see no tactical advantage to knowing which verticals people will not use against a back-turned Siegfried.
Also, it's infernally difficult to try to set this up in Practice mode. It's kind of discouraging to want to do so when it takes a minute to set it up, and then another to set it up again because you messed up, and then another because you're not sure you timed it correctly...it's a really big hassle for a miniscule payoff, in my opinion.
In conclusion, your time is better spent learning JagA.