XF 1.1 Paid Board Setup / User Upgrade Challenges

I would like to set my board up as follows:

New Users must validate their e-mail. When complete, they are automatically "registered" which only allows them to view content.

To post, users must upgrade for a 1x fee of $1.00 for permanent membership (MEMBER).

I also want a higher level membership with additional privileges which renews annually.

Challenge - I have 2500 users. I want to grand father in users that have at least 15 posts.

My first run at this I initially used an SQL statement to change every user with 15 posts or more User Group ID to the new MEMBER Group (which was 9). I had that user group to full rights but for some reason, those users lost ability to post or reply. So I reverted them back to 2 (REGISTERED) and changed the privs back to allow posting etc and things were fixed.

Any feedback? I think the biggest challenge here is the grandfathering old users.
Looks like that worked. Now my only issue is my 2nd tier user upgrade doesnt seem to be automatic. I'll ship that to another thread.