Practicing AR10 maps/maps on HR exclusively will not only frustrate you and barely help you read AR 10 better but you'll lose the ability to read lower ARs due to a gained tendency to play reactively.
Your rank is not high enough to "start and practice AR10"; I'm sorry but it's true; even I'm terrible at AR10. The best way to get better is to just have fun with the game. Seriously. If you really wanted to get better, I would try and get to 15k total plays (you're not even 1/3 the way there yet) before playing HR. For now, try playing AR 7/8 maps on double time.
Also, I highly doubt your edit to be true, but even if it were, that's not a reason why you should go out of your way to play differently. Even I've seen rank 10k-7k can't play with AR10 for the life of them lol.