It only takes about a week to be profitable, but to get a decent return back on your time, you really want to have CCU 5, which ends up being like 40% better at extracting P1. Then get IC 5 for the sixth planet and another 20% bonus.

I have a very optimized setup with IC 5 and CCU 5 on all characters across 2 accounts on 4 day cycles, doing about 2-3 hours of work every 4 days. I made about 3-4b/month from January to May of this year being completely self sufficient, producing an excess of P1 and P4. I reconfigured to produce twice as much P4, but now I have to source a constant supply of P1 from my alliance, but now I have been making about 4.8b/month.