OK, I've got my 70 reassembled. It was sprayed with DP40 right after media blasting. I have patch panel and filled. I am happy with the seam gaps and fit of the panels. It is currently mounted on the chassis. In order to minimize assembly/disassembly I am proposing this:

1. As it sits on the chassis, tape and mask all areas to not be painted.
2. Shoot a coat of DP40. then my filler K38 on the exterior of the car.
3. Block sand entire car.
4. Now disassemble and prime and color previously masked areas, i.e. underside of body,under trunk lid, under hood, door jams, etc.
5. reassemble car on chassis, mask all color painted areas, and seal and paint exterior of car.

I have read mags, seen TV shows, etc. and everyone has a little different way of doing it. One article said after trial fitting to disassemble car to fill and sand, then paint color, then reassemble car. They said to paint body with doors and trunk lid attached on a dolly, like GM originally did. Then reassemble on chassis.
It would seem to me to be better to finish filling and block sanding with car together, so alignment of panels can be confirmed.

Any help would be appreciated. I'll be glad when I'm done with this process!