Been there, done that..... I've bred plenty of males that were around the 300g range and they bred just fine. However, I've also had problems with a few of them shutting down on feeding. It's not uncommon for breeding males to forget all about food and it's not a problem with larger males, but with 300 gram males there isn't a lot of wiggle room in case they start losing weight. Although I haven't lost any yet, I have heard of other people losing males that they started breeding very small. However there is one that I had to start force feeding when he started rapidly losing weight and was looking very thin and getting weak. These days I'd rather wait at least until the next season. I guess I'm just not in that big of a hurry anymore.