hello my friend
It all depends on your patience! 3 SCROG plants can fill 120x80 if you practice intensive trellising (LST), but it requires work. If you don't want to wait 2 months of growth, add 3 clones as soon as possible. Just make sure they are a variety with a similar stretch to your current plants, otherwise your netting will be unmanageable. so as not to have too much of a discrepancy in size."
My little logistical tip:
If you add clones, try to put them in pots of the same size quickly enough so that everyone is on the same level. In SCROG, consistency is your best friend. I hope this will help you have a good evening