The first version was ready for the test!
I sent a few tweets to people who I knew where using Gumroad to sell their products. I wanted them to try the platform for free and give me some feedback.
I also got in contact with some "big sellers" and people who had a great following. My aim was to also get some more exposure on launch day if those people could recommend or mention it on their accounts.
I also asked for people here in Indie Hackers:
https://www.indiehackers.com/post/looking-for-gumroad-creators-free-access-for-feedback-b47a036855