Thanks for the feedback. Yes, top-ups are probably the most intuitive. That's even a step forward from the current one-time fee models IMO.
> LN-only recurring payments without a 3rd party
This is exactly what I'm aiming for with the spec, especially focused on self-custodial wallets.
See this test account, where a 1 sat push payment was done every ~10 minutes: https://se.oak-node.net/profile?pk=NPUB17XS6KVLERTM384UA6ZDY0ZV5HJPPL32832K55FD330L2TA3S6H0S8HV3SR
It needs a "helper package" on the sender node to schedule the recurring sending, a glorified cron job that triggers a LNURL payment with a memo.
I'm open to ideas, though, if there's a simpler way to do it.