Frustrated with inability to do body work!

Dura blocks are ok depending but I prefer an old school wooden/aluminum board. The longer dura blocks can be flexible. Ok, I seldom have to apply more filler over primer unless it's just a pinhole or something. When you work an area coat the whole section. When blocking when you first start to see the underlying layer whether it be metal or the next layer of filler down that is when you stop and recoat. Filler is cheaper then primer so I usually stay with that and I don't really like a layer of something different in the middle of the filler work. In my experience depending on the filler used some like to shrink overnight so once I get that first prime on I like to let it sit for a day or 2 or longer and re-block and prime again.