Worth it/possible to bi-amp fronts in 7.2? Denon X1800H, Polk ES55 FL & FR

Just upgraded my AVR and fronts. Discovered bi-amping while I was hunting for speakers. If I'm understanding correctly, I need a separate 2 channel amp to bi-amp the fronts (keeping 7.2, not going to 5.2). Is this possible and would the performance increase be worthwhile?

If so, what would be an affordable amp?

Viewing room is about 20 feet wide and 14 feet deep.