LC,
I wanted to comment on your post -
"E.g., A2 vs 5. If you hit and draw an A, you are allowed to say that you now have 24, rather than 14 (or 4), and double back."
You are allowed to do that, but you NEVER should. The reason being, you can still hit going forward and it does not cost you anything. However, when you have doubled and now cannot go forward what should you do? The strategy says to never doubleback on a soft hand because you are risking another bet. Here's an example:
You have A 4 vs dealer 5. In this game you should not double, but let's say that you did and you get a 9 for 14/24. You should not risk the extra bet to come back from 24; there are still two cards out of 13 that don't even get you back in the game. The best thing to do in that situation is to wait for the bust.
Many people think that you want to break and try and come back; that is not true. You want to try and better your hand and if you should happen to break, doubleback when the time is right. I have seen people doubleback on every busted hand, that is not wise. I have seen people hit hard 17 v 10 and it worked for them, but it still was not a good choice. This game just provides more options to the player and adds a little excitement.