I think if you ask ten people what type or brand of Primer to use you would get 12 to 15 answers. One thing I would suggest during your sanding and priming of the body, take a very small strip of tape and cover the emblems and lettering until you have gotten all of the other body issues straightened out. Only after all of that would I remove the masking tape for the very last light primer coat. Many builders here seem to prefer Automotive or inexpensive primers, and if that works for you then do that. I prefer to spend a little more money and use either Tamiya primers or Mr. Surfacer primer since it doesn't seem to "bury" the details when priming. I would use very light coats of Gray primer while working on the body since the contrast makes it easier to see the imperfections you are working on. When you have the body as smooth as you want it then paint your last coat with White primer. The lighter shade of primer seems to make most lighter colors that much brighter than if you used a Grey primer.