A billion copies to lead a communist revolution. Any more than that would probably be unsustainable globally in the short term while the existing capitalist systems are being dismantled and replaced.

Or 3 or 4 clone friends to help out with daily life.

Both are cool. The latter is probably easier and what my copies could actually manage.

Edit: Actually, the ability to sync memories is so ridiculously overpowered that one could probably achieve pretty much anything with their copies.

It also seems like its usefulness would scale up exponentially the more copies you make, so I'll go with the first one.