Looked like a beautiful surf to me! FWIW, I would do the same thing next time - and if he doesn't respond to the 11% in the same way then give him a higher carb food (and feed small amounts to try to keep him willing to eat). Also, the 68 at +4 last night and the 63 at +8 last night are basically the same number - we would call it "flat".
His AMPS also looks nice for a whole night surfing the greens - maybe a little higher from the MC but could also just have been the end of the cycle and the insulin dose wears off.
Do what makes you comfortable - and then just hear me out

From what I've learned, usually newly diagnosed cats (like Brian) do better with increases and decreases of 0.25u. Shaving doses is really used to fine tune a dose once you get close to a good one and also I've seen it used for cats that fail reductions consistently. Again, do what you feel comfortable - I really try to leave the dosing stuff to others with more experience than me. Perhaps
@Bandit's Mom can stop by if she's around later.
Hope you all have a good day!