Check the Preview Plans Again.....
DWG 11A should be included in your preview plan set. Here is a post from my blog about this very thing. Looks like I also posted something here on VAF. A little searching and you should find it:
......I did manage to squeek out a little time last night to start setting the 2 additional AN4 bolt nut plates that go on the inboard sections of both spars. Thes nut plates hold additional bolts that are used for attaching the wing spars to the center center of the spar that travels through the fuselage. I had to countersink the rivet holes for these as well, add primer, and readjust the hand squeezer depth to account do the the added thickness of the spar web and the support plate.
One note about this which I added to a post on VAF talking about similar concerns about poorly written plans. Vans mentions that the drawing that contains the refences for these additional nut plates is DWG 11A. I searched and searched my large plan set looking for this particular drawing, because I needed to find the rivet call out for these additional nut plates. But, no DWG 11A was in my set of plans. Then, after thinking about it for a second, I realized that the DWG 11A drawing is not included with the Wing Kit because the center section for the RV8 is delivered with the Fuselage kit, and NOT the wing kit. The RV7 includes the center section with the wing kit I guess, but not for the RV 8. Therefore, I had to resort to the drawing in my preview plans to locate the rivets for the additional nut plates, which are AN426AD3-6 rivets. This is perhaps the longest AN426 rivet I had set to date, but there are many more that are even longer that are yet to come. THe rivet needs to be so long to get through the thickness of all of the wing spar web material........