Ok just trying to give you ideas to help. You know your house and your budget so you need to do what you can do given your situation.

Id do what I suggested and play w the temps slowly and see what happens. If you can get hot wide in the low 90s and let it gradually space out to the right side you should be fine. If you have UTH laying around I'd slap one or two on anyway not like that cost you a dime.