I agree with Ngjockey about the gain issue.Gain (i.e. amplification factor) is not very important in this context, and you have already opted for ~100W capability for the amp, so stick with that for now. However,
A TVC, or any passive device for that matter, needs an amp that is very easy to drive."Easy" simply means the following: the input impedance of the amp should be "benign" (high) -- a rule of the thumb is, 10kOhm or more.
Likewise and usefully, the output impedance of the source connected to the TVC (i.e. cdp, phono, tape, whatever, connected to the input of the TVC) should have be low -- rule of the thumb would be 1kOhm or less.
A practical way of determining if the set-up is correct electrically is simply to listen to mid-bass & upper bass energy. If it is notoriously lacking, there is incompatibility usually termed as "mismatch" in audiophool. WHat that means is, the source + TVC are outputting insufficient energy to drive the amp. ANother amp may sound excellent, with the same source+TVC -- simply because its input impedance is higher.