Actually, I think I'll do a spot of reconfiguring, to more closely mimic a WHM/cPanel backup, so yes backups grouped by date. This will help with my multiple backups to remote locations - the key reason to have backups consolidated (larger block size).
I'll consider a parameter, to allow keeping the backups split.
Ideally backups should run between the hours of 02:00 and say, 06:30 (accounting for runtime), so date isn't an issue.