For lack of a more scientific explanation, it is a crap shoot. I have had males that were 450 grams breed numerous females and not produce an egg. My original Spider male bred at 5 months old, sired 5 clutches that year, and had his first baby actually pip and hatch before he was 1 year old. I have also had 1000 plus gram 2 year old males not breed, but breed their third year. There really isn't any harm in putting a young small male in with 1 or 2 females (too much breeding at a young age and when small could have some negative consequences). If he wants to breed he will. Wether or not he can successfully fertilize eggs is up to the gods.
Good luck,