There are a few different ways to do Spillman channels, the way I propose requires holding onto a presigned transaction for unilateral exit. This is only needed if the mint is uncooperative. This is non deterministic so you need to store it alongside your seed. However unlike lightning if you lose it the mint can’t cheat you out of any money by settling a bad state.

You can make the users unilateral exit path deterministic by implementing it as a timelocked script path instead of a timelocked presigned transaction. Then you only need your seed and nothing else to unilaterally exit.

However I like the presigned tx model better since it results in everything being a musig spend.