When I researched what to use for my backup I found rsync.net. They have some nice features nobody else seems to support, like they support ZFS send/receive https://www.rsync.net/products/zfsintro.html
But in the end the price made me go with borgbase.com
As for timing, one could use the flock function to ensure only one process starts. Something like this (untested):
flock -n ~/.htop.lock -c htop