I think there is a lot of marketing going on with the product systems. I like to create my own. This forum is a GREAT place to learn what a product actually is, what it really does or does not do. Armed with this knowledge one can try many different combos that will work.
One of the bigger things to consider when putting together your own "system" is whether or not the final polish you intend to use contains oils, fillers, and wax. If so, you are limited to carnauba or 1z Glanz (possibly others I'm not aware of) for protection unless you first remove these things your finishing polish left behind.
Some "systems" I've used successfully:
1) 1zPP - Souveran
This takes full advantage of the fillers in the 1zPP. Looks great, not much durability, quick and easy
2) 1zPP - AIO - SG
The AIO is only necessary to remove the fillers/wax the PP leaves behind. The paint is already clean and oxidation free from the PP. I'm going to try a thorough alcohol wipedown between PP and SG instead of the AIO. I'll bet it works.
3) 1zPP - Sonus Paintwork Cleanser - SG
Using the SPC in place of the AIO, you get a little abrasive action going while you remove the PP fillers for the SG. I think this makes the final results (after several coats of SG) better.
4) 1zMP - Glanz
Based on my lengthy study here on Autopia, I think the Glanz removes the 1zMP fillers. I can't be sure however, because the car I did with Glanz was virtually scratch free, even before the MP application. The point is that Glanz works over the fillers where SG does not, even though both are synthetic sealants.
5) 1zUP - AIO
This is great for paint in bad shape. The aggressive UP removes the oxidation and lighter scratches, leaving a finish that is just fine for a junker. Using PP after the UP will of course make it look better. That is, if you can stand devoting that much more time to a car that really needs some major paint correction via rotary/wetsanding.
Know your products. Create your own systems. You'll probably find you can often eliminate a "recommended" step. For example, I've been unable to see a difference between PP - AIO and PP - MP - AIO. I use PP or MP, depending on paint condition. Using both seems a waste of time and product to me.
NOTE: I've only had the Autopian bug for three months now. If any of the above is corrected by a pro, or someone who has a lot of experience with many different paint care products. please heed their advice.
Oh, I have a digital camera now. I'll be uploading shots as soon as I figure the thing out. I'm getting good results these days. It's time to start showing off my work.
Mikeman out.