I think your guess is right. The Cantons may need more power, and the ability to drive varying impedences better.
I'm sure many will have strong recommendations for speakers to try, but you may end up finding you won't be happy even with the Cary. Think about how loud you listen, and to what type of music.
If you think it still will be a good fit, I can recommend the Reference 3A MM De Capo's. Easy load, 92db efficient, and no crossover per se. You'll give up bass depth, but that can be added with a sub if needed.
Goodluck with the Cary's; I haven't heard them, but used to own 2A3 (SET) mono's, and they CAN be magical !