The word I got through the grapevine is to double up the F-310 and F-311 bulkheads, with the flanges back to back. Apparently there are sometimes, on some ships in some operations, some loose rivets back there. Don't know that first-hand but I'm taking that advice. On my F-310 pair I'm putting the stabilizer bars in between the two bulkheads.
The tail gear attach bracket is from the RV-4 and is slightly longer than the RV-3 design. Its aft flange is bigger, too. Things to deal with.
Another thing is that the control mixer can be placed almost too low, and to avoid that lest the pushrod interfere with the belly skin.
Don't know if you've checked my blog here on VAF but I described how I used 1 x 1 x 1/8 for the top longerons and narrowed them down to 3/4 x 3/4 in between where I wanted them wider.
Dave