I've only just started building and still on the first plans page. I got to the step which says draw rivet lines on the HS-00001 as per the drawing shown below.
When you look at the part it's clear that the 3/16" and 1/4" dimensions can't be correct. I rang Van's and they confirmed it. The dimensions are actually 3/8" and 1/2". So it turns out the problem is that the plans I'm working from had a number of errors including the wrong rivet callouts and a few of these drawings managed to get out to new builders. Lucky me was one of them.
This is the drawing (DWG3 R3) with the errors.
And this is the drawing (DWG R4) that corrects everything.
If you happen to be using DWG3 R3, there is an updated and corrected DWG R4 available from Van's.