I think he is looking good. At some point, you might try one unit again or a skinny one on the pinks, but for now, I think I would give it time. His pre shots are gradually dropping and the nadir is nice. And the Vetsulin seems to be lasting longer than 8 hours, which is great.
My thinking is that he is very new to insulin and the wet food and sometimes they take awhile to work together before things start dropping lower. Maybe reevaluate and increase by a smidge in a few cycles if you are still seeing pink pre shots and safe, blue nadirs?