Our machine is roughly 3600x1500, and we have two 25HP pumps.
So yes, another pump will definitely help.
Not sure how the current pump is connected, but I'd try to connect the second pump separately to the plenum, if possible, for more flow.
What we do on small parts, is onion skin them. All small parts are first cut within .25mm, then a second pass cuts them free. Once all smaller parts are cut, then we cut the larger parts in a single pass.