I finished the SB a few days ago, I had no real problems but I had easy access to the forward spar as it was out of the stabilizer.
For the RV-8 be aware that the new rivet hole that is drilled nearest the relief notches can leave you with very little edge distance in the spar itself. I've edited the image below to show what I'm talking about.
I spoke to Vans about mine, they weren't particularly concerned but nor were they giving any absolute assurances. I figure if it cracks it will relieve straight into that rivet hole but I'd recommend that you don't go crazy relieving those notches. Mine were exactly as per the drawing and I still wound up with this.
