I mean ... I'm not actually sure if it's contributing? It's only about 3.5% carbs, after all. Cutting out dry food has a variety of health benefits, but in this case I don't know that it would make a significant difference to has BG. If I understand correctly (and honestly there's a fair amount of material I haven't read yet), the reason that you're not supposed to feed dry food for TR has more to do with the speed at which the cat's system processes it (which was not taken into account in formulating the method). There are other arguments for giving up dry food more generally, of course, but I'm not sure they're as directly linked to BG. But also, I may be drawing some fairly confused conclusions! I'm just not sure.
The reasons I haven't wanted to just take it away from him entirely are that a) if he refuses to eat much wet food and I give him a shot, his BG could take a dive when I'm at work, and b) he's already pretty significantly underweight and just starting to gain back towards where he's supposed to be, so I'm balancing different health factors. That said, I might try it when I'm home on Wednesday or Saturday, and see what happens.
Your thoughts, and
@Tyleete's, on not taking reductions strictly according to the SLGS method make sense to me, and I appreciate your input and support!

I also know that a considerable amount of work and testing went into putting the method together, and that I am still struggling to understand what I'm seeing with Gen's cycles. While customization can be necessary and ECID, I'd really like some input from people who have been around awhile (and have therefore seen a lot of different cats' spreadsheets), especially those who have specifically encouraged me to take reductions, like
@Christie & Maverick or
@Wendy&Neko.
(I'll be talking to my vet about all this as well, probably tomorrow! She has tended to support waiting a week between dosage changes to give them a chance to fully kick in, although she's also been somewhat dubious about some of the reductions and the .25u increments for increases.)