Artcraft Vs. Pcs Vs. Both

Hi. I'm new to this forum and also a recently returned FDC collector (I collected Australian covers as a kid, but the internet makes international collecting much easier). I had started collecting USPS covers until I realised USPS don't do cachets. I've since been collecting ArtCraft by theme (e.g. military, architecture, vehicles).

I'm now trying to get my head around what cachets are available for each set of stamps released. When looking at some of my sets, where there are a set of stamps issued, there seems to be a single ArtCraft cachet used on FDC's with single stamps and with complete set (e.g. se-tenant block/plate block). There are also other cachets matching pairs of stamps (ArtCraft and PCS logos on them).

For example if I look at the American Architecture series' (79-82), I have FDC's with the same cachet showing all four buildings in the series with a single stamp and a block of four (ArtCraft); i.e. five covers with the same cachet. I also have FDC's with se-tenant pairs of stamps and cachets matching the two stamps on it (ArtCraft and PCS).

I also have sets of stamps (such as the 50's Sporty Cars and Mahogany Speedboat series') with unique PCS (no mention of ArtCraft on cover) cachets for each stamp and a single ArtCraft cachet with complete sets and pairs.

Is it safe to assume that ArtCraft only produces a single cachet for a stamp release and no matter what combination of stamps on a cover you order (new) from them, you will only get the single cachet?

It seems that there was a collaboration between ArtCraft and PCS over the years (maybe 80's and early 90's). But I've also got PCS covers, that look like ArtCraft cachets, from the 00's. Did the collaboration end sometime in the 90's? Are PCS still producing covers?

Finally what's the best reference for ArtCraft covers, and does it also cover the ArtCraft PCS covers?