RE: Let's try again DL-50
On that Yak, Paul, mine were tight also. Wrap a 3" strip of 80 grit around a 1" dowel that's 24" long. Glue to the dowel. Carefully sand the SOCKET of each wing, using an in and out, twisting/rotating method trying to keep it evenly sanded. Check the tube fit frequently. Mine didn't take much, and as I recall, the ply root rib ended up being the real culprit as it overlapped the socket slightly, creating the bind on the tube.
Don't get real carried away with the sanding; a little is all that is needed...
(sorry for off-topic)