Bi-Amping Which amp for highs and which for lows?

Pick the better amp of the two and biwire rather than biamp.  

If you decide to go for biamping have you confirmed that both amps have the same gain?

What would the advantage be of adding another crossover (the capacitor) ahead of the HF input of the speaker?  

I think the OP would need some decent measurement gear to get that volume control set correctly.

I still am of the view that bi-wiring with the best amp rather than bi-amping with different amps is better approach, but I wish the OP success regardless.

OP, suggest you confirm that the two amps have identical gain.....

If the amps have different gain, you won’t be driving the HF and LF sections of your speaker equally.  If the HF amp has 2db more gain, then it’d be as though your HF drivers are 2db louder than they should be.

If you are happy , that’s all that matters and you can safely ignore this thread. :)

On paper....  :)