Hyper-V new full backup onsite and offsite
Hello Arjen, @QiQQ
We provide our best practicies for a reason. Full Backup on at least monthly basis is needed because otherwise it will take significant time during restore to just construct the actual data that will be restored - not to mention that at some moment, if there's no near Full, just the download might be even bigger than that of just Full backup.
So, I would suggest you a counter-proposal of sorts:
Onsite - we suggest Full once a week, though it is up to you about the schedule;
Offsite - Full once a month, because in other case it will add up time to just reconstruct the data.
Also, we do have a feature called Synthetic Full Backup which can significantly speed up the Full backups (Image Based ones). This seems perfect for your offsite (however, it's only available for Amazon S3, so kindly take this into consideration).