Charles, A year ago when I started my body work I invested hours and hours researching methods and materials. It is my very first time working with fillers and paint prep. I could tell from reading numerous forums that there are a few really open and knowledgeable guys out there who don't follow 'party' lines and offer knowledge as opposed to opinion. ( I'm nothing but opinion myself except for how well the epoxy sands when cured)
I checked out SPI's painters forum finally and realized several of the guys I had developed the most respect for based on their posts in other forums were posting there. But what sealed the deal for me was being able to speak directly with the guy who makes the products and ask him questions even about other products and get answers that addressed my questions not some sales pitch why one is better or worse than another. Also SPI doesn't make Base coat (other than their red) and focuses on Primers and Clears. Check it out you'll be glad you did.
Oh and if there is no jobber near you they ship direct. Hard to beat that if your rural like me and the nearest jobbers an hour away.
Good luck on the project

Give me ambiguity
or give me something else