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

wow, i did not know you could do such a thing.
is bi-wiring preferable to bi-amping in a dual driver full range enclosure? i am building the Castle MT with Alpair 7 drivers

If the speakers have separate binding posts for highs and lows, then, yes you can run two identical runs of speaker cable attached to a single output post on the amp and each binding post on the speaker. Don't use the A and B posts on the amp.

Thanks Tomcarr

I am running the highs with the A5 and the lows with the A2. Speakers are P-37 and they do sound awesome. 

That's great!
Enjoy the music!!!