We have this setup for a few clients and in nearly all cases we have used backup copy jobs for rotated media.
in Version 7 we used the registry keys to force create the full vbk and clear the all data.
it works reliably and doesn't impact production. We just needed to take into account the data size and the backup window.
As we were rotating the drives each day/night everytime the job ran it would take while as it was having to recreate a full.