I heard so much about how brilliant the skin fits are on the Van's kits that I was somewhat shocked when I saw the bulge on the bottom of the tank skin where it joins the leading edge skin.
I discovered someone else experienced this (Tod Moeller) and found the same cause - a fault in the bend pressing of the flange tab leaving a bulge.
This was removed as best as possible by using the hand seamer and the scotcbrite polishing wheel