Biamping, bass and amplifier type.

I really want to thank everyone who has responded to my post for their well reasoned, thoughtful and well written replies.
Class (A) all the way.

I agree with Bob, save yourself the cost of an additonal amp and get a quality subwoofer. A subwoofer will produce way more bass than a biamped speaker.

I've biamped in just the way you're considering: a ss amp to the bass cabinets of my vr4 iii's, and dynaco mk iii monoblocs powering the mids and trebles. Though my ss amp puts out 170wpc, and the Dynaco's are rated a 60w, gain difference is not an issue b/c of two convenient configurations in my amp and preamp: 1) my ss amp has volume pot (per channel, but a single pot controlling both work just as well); and 2) my preamp has two sets of outputs. Those aren't requirements by any means, but it makes bi-amping a cinch. I keep the volume pots on ss amp at about 4, and then leave them alone; everything is controlled via the preamp, and I don't notice any imbalances across the volume range. And with the VRiiis, which get down to about 20hz, no subwoofer need apply.

I disagree with Stewie. He's gotten lucky with gain. Many amps will increase at different rates. Some amps will double output with a quarter turn while other only go up 10%. There is no way to compensate for different rates of gain.