Hi Charlene!
I'm not seeing that he looked better at 3.75 than at 4.0. One thing I'm noticing though, is that when he starts to make progress and get into better numbers, you've reduced the dose. Normal blood sugar for a cat on insulin is considered to be 50-120. It looks like you've reduced when he's even in the 160's. There are no numbers under 50 on his spreadsheet that I can see, so if you're following Tight Reg, he hasn't "earned" any reductions. If you have concerns about shooting low because you're going to be gone or can't monitor, then you could give a one time reduced dose, but you would return to the previous dose with the next shot.
Are you hoping to work for remission or are you just wanting to maintain him on insulin? It would be helpful to know what your goal is.
If you're wanting to work for remission, or wanting to protect his organs from the damages of high blood sugar, I'd encourage you to familiarize yourself with how cats typically respond to normal numbers. I wrote up a little and put in some spreadsheets for Darin a while ago. That post is
here. I'm thinking that you may be worried about shooting lower numbers because you anticipate that it might send Java really low. Take a look at that post and look at the spreadsheets of the cats that have had that happen. Or current posters that shoot a full dose into normal numbers regularly include Marje/Gracie, Wendy/Neko, Sienne/Gabby, Elise/Max . . . there are more, but those are the ones that are coming to mind immediately.
As far as his dose right now, I think you're on the right track. One thing I learned with a high dose cat (punkin had acromegaly) is that the important numbers are the blood sugar, not the size of the dose. So I'd encourage you to not be concerned about the size of his dose - cats need what they need. It looks like he's gotten into blues the last couple of nights, so you're getting closer with the dose. I'd give the 4.75 a week or so to see what Java can do with it - hopefully you'll see some greens!
Hang in there, Charlene! It can be really discouraging to not see your kitty respond to the insulin like you'd hope. I think the first thing that would help you is to look at some spreadsheets of cats that have gotten their full dose while they were in normal numbers. If you feel more confident about not backing down the dose when Java gets into better numbers, I think that's really going to help things.