Testing a $9/mo paid newsletter tier for my IP licensing readers

I've got the same problem as a lot of you — five tools that each do 15% of the job. So instead of adding a sixth, I'm spending the next four weeks testing whether my free newsletter subscribers will pay $9/mo for one concrete thing: a monthly teardown of a real licensing clause, with the redlines. Not a community, not a course. One artifact. My question before I commit: is your tool overload mostly billing (you can't meter recurring properly) or delivery (you can't ship consistently)? Curious which one bites first, because my hunch is billing is the excuse and delivery is the actual problem.