The amps should be the same , and using an active crossover . Without a crossover , you would want amps with output trim. I agree with the one good amp rather than 2 lesser or different amps. Personally I think bi amping is a waste.
What’s the Right Power Amp Ratio For Bi-Amping?
Is there a “golden rule” or rule of thumb when selecting amplifier power in a bi-amp setup? It seems to me that the power should be apportioned according to the demands. Since most of the energy consumption in sound reproduction is by lows, it stands to reason I should use a much more powerful amplifier for lows than highs, but what ratio of power? 2:1? 10:1? Is there a wrong answer?