[crashtech]

I can't say I have the answer here, but I tend to follow some procedures that help ensure a job will have no visible problems from shrinkage. First of all, never feather filler up onto non-factory paint unless you KNOW it was all catalyzed and well cured. Second, never feather filler up over your paint featheredge unless it has been nicely feathered back with at least 150 grit, preferably 220. Third, make sure the featheredges are in 320 grit before priming. Fourth, let that primer flash off! Don't stand there and look at it, go do something else between coats, and set a timer if you tend to lose track of time. Fifth, don't apply thick coats. Just go one coat extra if needed. Now, I'm sure a guy could follow all these steps and still get shrinkage, but that would be rare, IMHO.