I think you guys might be safe to increase to 1.5u if you'll be around to monitor to make sure the numbers don't drop too much.
It might be a good idea to test for ketones weekly at least for right now. Some cats are ketone-prone, some aren't. Mikey has never had ketones so I only test him every week or two or if he's seeming a little off, but I did try to test him at least weekly the first several months of this Sugar Dance.