My suggies do not over eat. I've not seen an excessive amount of posts discussing them over eating, but if they feel they aren't getting enough food and are being territorial, there is something to "I'M GONNA EAT IT ALL ALL THE TIME" because of territory. Watch their weights, of course, but also keep in mind that someone needs to be fed. And if they aren't getting enough food, the first step is to get them fed up. keep playing with them, keep loving them, give them a good diet (not too many fats, not too few vitamins... the usual) with variation. If there's a food one HATES and the smaller one LOVES, then it's a good idea to put that food in more with the balanced diet. For instance, my smaller glider would never eat tomatoes, so when she was having weight problems I'd be sure to feed her no tomatoes and give the other one other foods in a different place and give her her favorite foods in her spot. They got used to eating on different levels because the other glider always seemed to have "icky" foods.
keep trying!! You'll get a pattern set and a solution found!