How to design/calculate the disk spaces with rr(remote replicate) ?

Hi, All.

I would like to ask the ZFS disk space design calculate tool with replication.
Anyone advise me the our replication degination.

** Goal system.**
50 shares whose size is 3TB.(Excluded in the snapshot space).
Total shares size is 150TB.(usable)
Snapshot space should not be affected to its share's capacity.
So each share is set as "not included the snapshots" on share properity.

Generally I designed the disk space below 80% usage. (some issue for management bui).
I cannot find the guide or information about the recommendation disk space calculation with the snapshot consumption.
Because it had various disk space size use cases. It depended on how many snapshot be created and stored on pool.