If you move it forward you will need to move the motor forward, unless you use one of those drivelines that doest need a PTO. As far as bad handling from the pump itself being forward, you could always use a bowl extension or a longer droop/snoot to make up for it, couldn't you ??
Ironman and I have been talking about this same issue with his new project (same bottom same pump swap) and a few people have said, do not set a pump back on these boats, not sure why.

Keep me informed of what you find out, please.