Ok! I don’t believe this usecase is what autostop/start helps with.
So, to do this, the closest we’ve got is fly m run --schedule <sched>. Schedule doesn’t accept a time, though, it accepts “monthly”, “weekly”, “daily”, “hourly”. (for more info, here’s a post about that)
Unfortunately, I don’t believe we currently offer granular scheduling at this time. It’s either the loose “daily” scheduling, or keeping the machine running indefinitely and just running something like cron inside of it.