Don't do this. It's very bad and slow and builds bad habits.
I have some experience with OH, and to relearn fingertricks the main thing you want to do is to force yourself to use the proper fingertricks during solves or practice. It will be slower at first if you are used to the bad fingertricks, but will eventually get faster with them. Your hand will also most likely get tired, so try to push past that for a few solves but always listen to your body and if it's too much don't hurt yourself.
Use this video to learn the best fingertricks and you should be set. Just remember practice is the best thing, and you will be slower at first but don't be discouraged, progress will come soon if you stick to it.
Also for which hand to use, left is the most common regardless of if you are right or left handed, this is mainly because it's easier to do RU moves with your left hand, and that is what almost every alg for 2H uses so it's easier to apply to OH without needing to mirror every alg.