That's kind of like asking how much a fully-grown human will weigh. It depends on how much they eat and when, how much energy they have to expend, and what their genetics are.

The largest male I have varies from 4000g at the end of the year to ~3600 grams when he resumes feeding in late spring or summer. But he seems to be an exception. A 2500 gram male wouldn't be unusual.

Feed him all he wants when he's young and take good care of him and he'll reach whatever his optimum size is meant to be.