My gems/enchants posting on a massive pop realm goes like this for me:
- high selling gems: stack of 20 on my seller, list 2
- low selling gems: stacks of 5 on my seller, list 1
- sha crystal enchants: stacks of 20 on my seller, list 2
- other enchants: stacks of 5 on my seller, list 1
I continuously repost, till I start to see empty holes in my bags. Posting cycle can take up to 10 minutes on peak times (AH is soooo slow).
Then I cancel all gems and enchants. And restart the continuous posting cycles.