I have a 2002 white Toyota Camry. After following several threads, I decided to go with Poorboy's (PBs) for the whole treatment (minus a few items).
I washed with NXT and clayed with Clay Magic. You can combine these steps and use the soapy water as the lubricant (Wash surface, rewet if necessary and run clay across it). This is quicker than washing, drying, lubing, claying, rinsing and drying. Next I polished the deep scratches/swirls with PBs Super Swirl Remover (SSR) 2.5 using a Porter Cable Random Orbital Polisher (PC). I followed that with a full car polishing using PB's SSR 1. Then based on other recommendations for white, I applied 2 coats of PB's EX-P, a sealant, for long-term durability. Finally, I put on a couple of coats of PB's Natty's Paste Wax for a warm glossy look. At least once a month, I will add an additional coat of Natty's to combat the hot Texas sun. I repeat the process as needed or about every 6 months to keep her purty.
I like the fact that I can buy all of polishes/sealants/waxes at one spot. The reason for two coats is more to cover user error (i.e. missed spots) than ensuring maximum protection. I'm still pretty new at this so I haven't tried many alternatives. I would recommend setting aside a full weekend for your first go at it. Time flies as you work through the processes and try to figure out if that is what the product/paint is supposed to look like at that stage. Sealants also require 12-24 hrs to cure before a second coat.
Hope this helps.