always good to hear the same maker's pre and power amps... they obviously afford the owner the desired synergy intended
for me -- i found the cary slp98 too veiled, slow and syrupy for my tastes
i have vlad’s 6c33b set mono amps myself, they have a degree of warmth and solidity in their sound ... i would strongly suggest a more extended, clearer tube pre, like one of the more modern c-j’s (et5 or et7-2) if that can fit in your budget