I have used this stuff and alot of their other paints...I agree with you on the directions because they are confusing. Luckily I got a book with all the products and read on the website too before using. You have to wait till it is completely dry before painting. Then you need to scuff the shine off of the POR 15, wipe down, let dry, then paint with Blackcote. It is definately a long process but all I could say when I was done was WOW. I painted my engine bay and my underbody with Whitecoat, it looks excellent...I will be posting pics of the car when I am done but right now I need to finish building the motor and then install it all, so it will be a while. I only used the POR-15 on my subframes where the car had developed rust from the jacking points. I tested it out with a hammer to see if it would hold.....and it did.
I have painted all my suspension parts with the Blackcote as well, LCA's, PHB, Sway Bars and so on.
I will most likely be painting my rear with the POR 15 and Blackcote as well to keep it looking good until I have enough for a Midwest 9''.