Cornwall IV's with Accuphase E-650? good match?

this is good thanks

and yes I switch a fair amount, maybe not the right way to achieve things buts its been fun thus far

I didn't mean that in a negative sense, switching things up is the best way to figure out what you like and can be very fun.  Sometimes the hunt is more enjoyable then the meal.  Definitely get some experience with Accuphase, it compliments speakers like Klipsch that run slightly on the cool side of neutral, and should be easy to sell on if you don't like it.

A nice tube amp and you’ll be ecstatic. 

probably work well but why spend that much for power you'll never use. I'd suggest if your an Accuphase guy one of their lower powered class A amps.

That said a SET tube amp would be ideal for Cornwall's, friend added a SET300b amp (8wpc) it was a stellar combo, very musical and inviting. 

I am currently using a very robust designed rawsonte FW F4, and the sound quality I am experiencing through my Lascalas, is possibly the finest in a very long time. Let me add, prior I was going passive, but a preamp is necessary with the F4. Unlike tubes, speed, control and balls to the walls bass. If you like these characteristics, above adding color, get class A ss. The preamp / F4 combo, is uncanny.