[quote user="igglebert"]...that'll be fine, will give the bass plenty of dynamic headroom...[/quote]
With this simplistic type of bi-amping You will get more "dynamic headroom" on the bass if you use the higher powered amp on its own, that is unless you mismatch the levels to make the bass higher. Matched power outputs on the amplifiers used are a must. Here's a comprehensive article on the subject.
http://sound.westhost.com/bi-amp.htm#basics
And another opinion:
http://www.gcaudio.com/resources/howtos/biamping.html