How much do you charge for application fee in Stripe Connect Express?

Hello folks,

I'm currently working on a marketplace project similar to Etsy that integrates with Stripe Connect using an Express account to pay the sellers. We're still undecided if a 12% application fee is reasonable for the connected accounts holders.

We're also thinking of having a minimum amount per transaction to at least cover the active account fee of $2/month.

How much do you charge for the application fee? What's your pricing approach for Stripe Connect?

Thank you.

Note: The maintenance of the project is very low at the moment. Cost us around $25/month to host it.