Dynaco/SS Bi-amp w/ Von Schweikert query

The tube bug has been hitting me lately, and I'm interested in bi-amping my VR4 HSEs with a W. Vincent Dynaco 70 for the mids and highs, and my Kenwood 700m on woofers. The 700m has an output of about 190 wpc, but it also has r. and l. volume pots. Preamp (Kenwood 700c), thankfully, has two sets of outputs.

For the pros out there: how likely is it that I could establish an output balance between the Dyna and the 700m by setting the volume pots on the power amp? No doubt you could balance them at a particular volume, but is it likely that the balance will hold when you change the volume via the preamp pot?

Also, is anyone using the Dyna 70 VR combination, biamps or otherwise?

Thanks in advance for the help.