Sorry it was such a hectic night for you both.
My guy is quite big, he was up at 20pounds before his diagnosis, and he's strong too. I take it Henry is food motivated, my George is, and that is what I used to help me test him, my husband was working away at the time so I had to learn to test him myself.
I used a small piece of freeze dried treats, with it I would get him to come sit on my lap, I would also rattle the test strips. He learnt that if I rattled the test strips, that meant a treat and he knew to come sit on my lap. I would test him while he sat on my lap. He got so used to being tested that I would often just go and do the ear prick where he was lying on his bed, there was no need to pick him up or handle him.
I also get your problem with the food, George also needed to loose weight, there were days when I had to feed to keep his BG from bottoming out, and it would frustrate me, but I had to feed what he needed to keep him safe. It meant his weight loss was slower, but he still lost, you won't need to be steering him with food every day.
One interesting thing for us that making the switch to a wet diet, really helped his weight loss, it happened slowly, he'd been on a prescription kibble diet for years, he was only allowed 65g, he was starving all the time and lost a little weight a couple of pounds but stalled, and he was miserable with it. The wet diet saw him happier, and more satisfied after a meal. He now weighs 14.5pounds which is a good weight for him. What I tried to do with the food was pick foods that were LC and lower in calories, avoiding those that were more calorie dense, it gave me more wiggle room for feeding. I also tried to get him to play, which wasn't very successful he's an old boy, (21 now), but that might also be something to try to help him with his weight loss, he did get more active when his BG was in good numbers so that helped, when his BG was high I guess he felt crummy so he slept more.
He still managed to loose the excess fluff during his diabetes treatment, and when he got into remission he got down to his ideal weight. He stays quite stable now.