At the end of my article I propose a separate NIP specially for Sponsored Events (notes, reposts, reactions, etc) that uses the ASS NIP that is too generic. Fortunately selling follows won't work well, because it is a replaceable event and cannot be proposed to multiple people at the same time 😂
Discussion
Just solve for the most specific problem and generalizations will fall into place automatically in later versions.
I'm trying to figure out the generic version in order to propose changes to NIP-07 and NIP-46 for it to work with extension and remote signers. As of now, one of the parties need to sign in with nsec in order to generate an adaptor signature, since other signers do not support it yet.
Send a nip pr with the extra method to 07 and 46 in the best way you can define and let's see how it will go.