How to determine OEM license pricing?

A customer of mine is asking to use one of my plugins in a "Wix" like service (customers can build there own sites which then will use my plugin on the front-end). I've asked them the number of sites this system will potentially be used to create and it might run in the thousands.

Any articles or tips on how to determine the price point?

How about a custom extended enterprise license with bracketed pricing?

10-100 sites $29/yr per site
101-249 sites $26/yr per site
250-500 sites $24/yr per site
501-1000 sites $21/yr per site
1001-2499 sites $18/yr per site
2500+ sites $15/yr per site

Then get an estimate of sites they might get per year and agree on a contract for X amount of years.

Just thinking this out 😜️

Thanks, something to think about :-)