Add me as well to percentage over flat fee for the services.

Heres something i havent seen mentioned: have it stated clear-cut that your website is for CREATORS and THEIR creations. There are people who use Pareton's services to gain money, and then use said pledge money to pay people to create their patreon content.
Please make it clear that your service is for creations the account owner makes themselves. Since people who do the above like to say its ok, when its not, because patreon's wording on the situation could be taken either way.