I never use X pattern.
I did a bunch of blind test with about a dozen people over weeks using a few different 4x12 cabs and several different Celestion.
No one ever picked X pattern. Everyone always picked top / bottom.
I have heard X cabs I liked. But often they sounded best when you are...
Andy Marshall lent me a Hot Mod V2 EVO. I tried it in a 2 channel Mesa Triple Rectifier, Orange OR50 and THD Series One Plexi(69' smallbox clone). I recommend replacing one of the 12AX7 with a 12AT7.
I tried the Hot Mod V2 EVO in 3 amps. One was a Plexi Small box clone. Andy Marshell let me borrow It. It definitely can add a lot of gain. It takes about five minutes to put in or take out of a amp.
There is a few different models. I don't know what one works with the KK.
As for pedal and...