Science & Industry

I do something completely different to you in that I just sell the P1, but what I do may help you at least get the P1 part, I do my PI in null (for better yield). I hate the micromanagement in PI, I do it literally in the laziest way I can think of to give me a bit of pocket money, it is with 16 planets over 3 characters.

Each P1 planet has 6 basic factories, 2 x storage and 1 x Launchpad. Plus 1 extractor with 10 heads. most of my toons have PI still to IV (accept 1 which has them to V).

My extractor with 10 heads runs to one of the silos, they feed the raw materials to the 6 basic factories.
The output from the basic factories goes to the Launchpad
The 2nd silo is there in case the first silo gets full and I expedite most of the material to that silo (which is also linked to feed the factories.
I run 2 day 1 hour cycles (the max that can be run as 30 minute cycles)

Notes: on some planets the silos are pretty full by day 2, so I wait 3 days before setting the cycle off again (so it gets rid of backfil)

The Launchpad will fill probably once a week. If I cannot be arsed to do more PI, I launch in a frigate, sit in a safe and just transfer the p1 from the LP to the POCO, then collect everything every 10 days maybe).

Also when I did run P3 items I used 4x silo and 2x launchpad, I upgraded ALL the links between LP and silo to 160,000 then the re-do time after moving stuff around is 5 minutes.

EDIT
If you are using 2 extractors to take 2 different materials you could increase your PG/CPU efficiency by having 1 head doing 1 product for 2 days then the other product for 2 days. after the first set you will actively add to one pile whilst using up the stored stock of the other items in making P1