I lost track of how you guys were dosing (twice a day, TID, every X hours, at a certain cutoff, etc?), BJM, if you could refresh me, that would be great.
I'm not sure that his higher numbers are due to him being lower yesterday. You are providing more foods, and as his body starts to compensate for some of the stuff going on, he will probably start needing more insulin. This seems to happen. Don't be afraid to give more insulin to keep his numbers down. Goal is under 300 at all times. Better if he can stay near 200 for most of the day.
I don't have a ton of prozinc experience, and for me it's easier to have a consistent dose (rather than sliding a dose) so I can see if patterns develop. I use Lev, so my approach is quite different, and BJM has a better understanding of the nuances of prozinc. My advice, however, is err on the side of a higher dose if you can't decide.
Oh and congrats on the lower ketones. That's a good thing.