Never played a KK with 88s, but a buddy used to have an '83 2203 that he used with 88s. It was a very slight variation over our 2203s with 34s and 6550s, but not by much. We can tweak all day, tube swap, etc...but an amp will never deviate too far from its core tone unless you're gutting it and making it something different entirely.
I've tried this route before of trying to squeeze a tonal square peg into a round hole and make amps sound like something different. I wasted a lot of time and money going down that rabbit hole, and finally reached the conclusion that when I wanted a different flavor, it's best to just try a different amp rather than continue buying the same ones over and over and hoping for something different. That's just me though, YMMV. I agree with the folks above advocating trying something new.
