[mikeyj350]

I remember reading this exact step aloud a number of times before I finally understood it. The second sentence of that step is indeed a mouthful and can be confusing. Yes, countersink the holes in the FORWARD row that are in line with the fuel tank attach nutplate holes so that an AN426 rivet will sit flush (same depth as the nutplate rivet countersinks). Later on, the aft row will also be countersunk, but deeper to nest the wing top/bottom skin dimples.

In other words, of the two rivets on top and bottom that attach spar flange-to-rib, the forward rivet is flush beneath the skins, and the aft rivet goes through the skins too... requiring different depth countersinks.

If you goofed and countersunk both the forward and aft holes though, you're in luck... you'll just need to dig the aft ones out a bit deeper later on!

P.S. A potentially helpful post from our blog with semi-ok pics:
http://mikeandsarahrv10.blogspot.com.../wings_25.html

Enjoy!