At only 6 months old I would give him more time. Females can be really aggressive toward a male's breeding attempts so it may not be the best idea to a really young male in with a large female.
I agree with them. I have a 6 month old that bred to my female SS but he was hitting right around 60 grams. He is a chunker for that age too for not being a giant. Males really should be 50 grams no matter how old they are.