The long will help on the sleeve front, however, you might fundamentally have a balance problem:
I am not a tailor, and balance on RTW isn't much of a problem for me, so I don't know if it is correctable in your case.
You may want to do a proper photo in a long, and post in the ask a tailor thread. Or, you may want to try other brands entirely - this may not be a brand for you.
Finally, as I am not a tailor, you...