Most folks wear an ankle gun on the inside of the support side leg. To bang the center console I’d think you would need it on the outside of your right ankle. Other than Sonny Crocket, I haven’t seen anyone do that. 
I did it. Allowed me to do a crouching “same leg” draw which was more practical than the roll on your back like a turtle method which can startle your attacker into shooting you.
There was an additional consideration that I tend to use a front left leg kick to my attackers leading leg in situations where things have started without my knowledge. Can usually fly that one under the radar while they are busy looking at my hands up in front of me guard “fake surrender.”
But yeah, I was wearing it on the outside of my right leg.
I see what you did there 
It sounds like you have put a lot of thought into your options and I always believe the more “what-ifs” you go through the better. However you need to be careful of making your conclusions absolute.
I think any sudden move in a tense situation can elicit a negative response. It’s all about having lots of tools to solve problems. Falling to your back is also a tactic for taking shots in a crowded environment. Falling on your back can also be where you don’t choose to end up. Where is the suspect and his angle of attack? What are your options for escape or to create room? The more options and training the better.
Note: I have no problem with full size strong side OWB in any weather and I’m not that big. It’s all about the proper cut of your clothes and the right holster for you, and I don’t mean huge like the 5.11 shirts. Plus a backup or two depending on what I’m doing!
Dennis.
And that is the main issue. Time to an ankle carry, regardless of method, is longer. This is why I’m more willing to directly engage a threat and buy time to go for my gun then pull of some ninja rolling draw and get shot for my efforts. I’ve seen that back rolling draw go bad more than a few times.
I’ve never seen or been taught to do any kind of roll or movement onto my back when drawing from the ankle. The draw I use and see others in my agency practice includes grabbing the pant leg and lunging onto your sting side knee while stepping forward with the support leg. It sounds like what you described for your ankle draw but the gun is protected during day to day carry because it’s on the inside of the ankle.
I borrowed this photo from BkueSheepDog.
I think we all agree that an ankle gun has its drawbacks, but for NPE’s and as a 2nd gun (my use) it has value. I also will uncover it while sitting in a car with a CI in case things go sideways. I typically am behind the CI while my partner is up front with him. I can have my hand on the pistol without anyone knowing or appearing threatening.
Easy. SW Shield, front right pocket.
I’m not saying it is a guarantee that someone with their keys clipped to a belt are always pocket carrying, but it makes me look at a person’s pockets and usually I can spot their gun and tell you if it is a j-frame or semi-auto as they both print different.