Significantly lowering the revs_limit increases the risk of false conflicts appearing during push replication. If the client is pushing a revision with an ancestor that has been pruned away on the server, that revision will end up being treated as a conflict.
How low you can set your revs_limit depends on how your documents are being updated, and how frequently.
If you’ve got multiple authors updating documents frequently (every few seconds), then you’ll want to keep revs_limit more conservatively scoped - I’d say at least 20.
If you’ve only got a single author updating documents relatively infrequently (every minute or more), you might be fine with a revs_limit as low as 3.
I wouldn’t recommend going with revs_limit=1 - at that point you might end up with unpredictable results during both push and pull replicaiton.