i think if i were in your shoes, tamara, i think i would get a multiple compartment feeder and if i were worried about her in the morning, i'd put her in a bedroom with a little bit of food every 45 minutes or so through the middle of her cycle. i had to leave punkin today at a 52, and i set 2 compartments with a tablespoon or so of high carbs in each one of them and went out. one opened 30 minutes after i left, then 30 minutes later the other compartment opened.
when i have run home from school at 11am and had to leave again in 5 minutes and he was low, i set the feeder to open 4 times at 30 minute intervals to get him past the nadir.
the feeder has bought me a lot of peace of mind.
i don't think any of us can answer the question about timing - did you read the post on glucose toxicity and how diabetes works? the only specific thing i recall from that info was that Rand did a study that said in normal cats, a sustained BG of 540 resulted in almost no pancreatic action in 3-7 days. Ella's not at 540, i know cat's pancreases can heal and damage is reversible up to some point, but i don't know what that point is. i doubt anyone knows. you have to weigh out the risks. the flip side is that cats do tolerate high numbers for a period of time. beyond that, your guess is as good as mine.