How do I charge a bar for events as a self employed individual?

I have a good relationship with a bar owner where I organise and run a pop up 3 nights a month in their premises. They allow me the space for free, I fill the basement level bar with new patrons who buy their beer.

They have wanted to host more events outside of my niche but don’t have the time to do so. The bar man and manager is slammed and says he doesn’t want to do this part of the job. Which considering he’s the only member of staff is understandable.

I’ve proposed to them this could be something I could help them with. I want to suggest some paint and sip events, a rotation of pop-up food vans that can pop up weekly, and a couple of DJ events focussed on some more nostalgic subgenres as the basement is big enough to accommodate.

I’m formally a graphic designer who can design, build websites/book systems and know how to market things properly.

I don’t know how to propose payment. Should I be taking the earnings for each of these events and they get the beer money as before? Or should I request a monthly rate, or flat rate per event?

Thanks so much.