|Local PI Base|
First, what does my setup look like? Well, there are two setups I use. One is for "local" characters -- those who live where they can easily get to the PI system, to move stuff up and down to the customs offices. In the case of wspace, "local" means in the same system. Out in kspace, it might be up to a few jumps.
The second setup is for "remote" characters -- those who cannot just fly to the system whenever they want. My Jita market alt does PI in my wspace system, but only flies up once per week or so. The setup for remote is very similar to that of local, but it has a second launchpad.
In both cases, there is an extractor that I place right next to the control center so that it is easy to find. The extractor outputs to a storage. The storage is drawn upon by 6 BIFs, which then output P1s to a launchpad. It is possible with very high concentrations to put a 7th BIF in the gap in the middle of the design. The launchpad outputs to three AIFs which are making P2 goods. (These are shown at the bottom of the local base, in the lower right on the remote base.) The AIFs route back to their adjacent launchpad.
|Remote PI Base|
My system has some planets with very high concentrations of the resources I am extracting. Others, not as high. Also, on large planets links cost enough that you cannot get quite as much stuff, and our particular gas giants have mediocre concentrations of resources. So, this means there is substantial mismatch between the rate at which we make some goods as versus other complementary goods. We have addressed this in several ways.
One way to get a bit more of a resource that has a low concentration is to remove one of the BIFs, and instead add an extra extractor head. Each BIF can process up to 144000 P0s per day. So, when you are getting below 720000 per day, you won't keep more than five busy. Of course, if you are already running all 10 extractor heads, you cannot gain anything here.
A second way to deal with resource extraction rate mismatches is to import stuff. P1s are pretty cheap, and given that we are running a fair amount of goods outbound anyway, there are return trips that we might as well fill up.
A third way to deal with lower concentrations is to just extract more, using extra characters that we were not planning to do PI with. Our worst planets still get about 650000 R0s per day. The highest keep 6 BIFs busy -- so more than 864000 per day. It does not take a lot of extra extraction to make up the amount.
All of the discussion above relates to the vast majority of planets, those which are extracting P0s and turning them into P1s and then P2s. In addition, we also run a handful of "factory" planets where we make P3s. There don't need to be a lot of these planets, but the size reduction for making P3s is considerable and thus well worth doing. A factory planet can do some basic extraction and processing to make some P1s.