the chest is NOT a good indication of a glider being over weight. The chest is actually the healthiest place for gliders to store extra fat in preparation for torpor which can happen during the winter.
114 grams is within "normal" weight range, I wouldn't worry to much or change to much for that matter. He will probably gradually lose the extra as the weather gets warmer and his body doesn't need the extra energy source for torpor.
I've got 3 gliders that weigh over 140 grams and only one is overweight. My 2 neutered males are around 165 ish and not over weight at all for their bodies. Gliders size and weight are as varied as humans.