At how many grams can you sex a crested?

I'm starting to see the bulge on mine at 8 grams but with my untrained eye i'm not entirely sure. When can most of you positively sex?

Bulge wise it usually starts to really show around 15 -20 grams. You can use a jeweler's loop and look for pores after 4 grams. If they have pores they are definitely male. Telling female is a little harder as males sometimes won't show pores until 12 -15 grams. I had one not show until 20 grams.