A few people had asked about this and I should probably address it now since I'm going to continue using Patreon.

I post the previews of finished commissions on Furaffinity and full versions early on my Patreon. Commissioners are ALWAYS allowed to post their finished commissions anywhere before I do, even if I'm only showing a preview. I think it would be silly for me to ask commissioners to hide their bought artwork for 1-2 weeks until I post it on Furaffinity. I have no problem with this at all; the previews are just a suggestion to check out the Patreon and I'm more than flattered when commissioners want to share my work.
The only time I would have a problem with it is if someone besides the commissioner was taking finished work and posting it to their gallery or claiming they created it.

Hope that clears things up~