Always felt that high spots are worse than low spots & this is one of the reasons why I try like hell to get rid of as many of them early on as possible. Then if possible a light spot prime with a little flash time followed by at least one recoat feathered a little further out to get some decent build up where needed without a repeat sand through or thin spot. SPI epoxy pot life makes that a little easier than 2k.
Man some of those lower body lines are kinda like working on 70's f body rear spoiler sides, but in an awkward low position. Looks like one of those times when you actually try a whole selection from one of those goofy multi shaped foam sanding block sets along with finer or partly used paper.
Dolly looks like a pain saver working down low.
Your door gaps don't look too small from pics. Weight added to center interior area between the wheels hopefully won't affect them.