You may want to layer your clothes (binder, vest, t shirt, button up) to prevent people from noticing. That's what I do, usually, and it works pretty well for me.
You can try folding the straps on themselves a little to see if that helps with the length. Safety pin them until you're sure, and sew them that way if it works. That could also resolve the length issue.
As far as other binders go, I've tried probably seven different kinds, but the only one that's ever worked for me is the 997. Everything else just gives me uniboob, and I'm a DD. Due to the size of your problem children, I think full length is going to be your best bet. Underworks does also offer a t shirt style binder, so that might work better for you.