87 grams in on the larger side but I wouldn't say he is too fat. The "normal" weight is 65-90 grams but you have to remember in the wild they won't get to the 90 gram side, in our tanks with food every other day they can get a little bigger than wild ones.
How much does his weight go up and down? My adults will swing 2-3 grams depending on the day(think it's more to do with when they lasted pooped).
He's definitely a bit chubby. Geckos can have issues with obesity just like people. Side effects can range from simpler things like low energy or difficulty getting around all the way up to fatty liver disease.
You can try limiting the number of super worms and feeding only once or twice a week to help him stay healthy. It's fine to have a good tail store, but when the tail starts getting much wider than the neck, or they are storing fat on the back/sides, you know there's a bit too much.