Gain Matching of Amps

I seem to have two pair of ARC amps--a pair of VT100IIIs and a pair of D240IIs. Right now I'm passively vertically bi-amping my mains with the VT100s. I started wondering about bridging the D240s to mono for the bottom end and using a single VT100 for the top end. The specs for the VT100 say the input sensitivity is "1.9 V RMS for rated output, 23.5 dB gain into 8 ohms." The D240s say "1.6 V RMS for rated output, 25.8 dB." Does this mean that all I have to do is attenuate the signal for the D240 down by 2.3 dB, or does the mismatch in the 1.9 v. 1.6 V RMS spec mean I'm comparing apples to oranges?
You may use the passive volume controll towards D240 amp to tame its gain. Adjusting the tone balance to your ear will dictate the best listening conditions you choose.
try it and see how it sounds to you at your optimal listening volumn. The gains might be vary, but they might be just fine at your comfort level.

On my Kef speakers, the base eats lots of juice so, just for fun, I tried running my McIntosh (100 watt) amp to base wwith my unbalanced connections and my Audio Aero (50 watt) amp to the mids and highs through the balanced connections.

the balance is not perfect....but I kinda like it.
Thanks for the responses. Guess the answer is to dive in, see what it sounds like, and play around a bit. Nothing like trying to squeeze my head into the small space behind my racks and play with wires...