I'm no genius and still learning new things myself
I'm gonna tell you about some things to keep in mind when stressing over gliders not eating what you want them to eat.
we discussed already how and when to feed, but other things can affect their eating habits as well. The moon phase, barometric pressure changes , females in heat, not measuring out the food as I mentioned before, and some times they just don't eat good for a night or two.
I used to stress over it a lot, but now I can tell it's not just one cage not eating great that night, all 3 of my cages don't eat great on the same nights. After a couple nights of that they go back to eating good again.
Your guy is a single which I think also plays a part in their lack of appetite sometimes. My first girl Leela, didn't eat to great until 1 I figured out wth I was doing wrong and 2 she got a cage mate.
Having two gliders does tend to get them eating better, in my opinion. But as I said above, other things can play a part too, and sometimes they just don't like what you are offering them lol picky picky
You can also pick up a kitchen scale, and keep track of what he weighs. Weights will vary but if an adult is 55 grams or under that is a dangerous weight and he or she would need to go see a vet pronto. Anything above that is okish, most aldult ( 2 yrs or older) run about 100+ grams though some maybe less