I had some issues with interference of the position of my analog instruments (speed indicator) with the top fuselage center rib. The flange was interfering with the body of the instrument. Some articles back, you could see I tried to bend the flange of the rib but this was not succesfull. I cut off the flange of the rib until behind the body of the speed indicator to clear the instrument.
On the other side of the rib, I reinforced the rib with an aluminum angle. Simple fix for this problem.