I figured that particular area was going to create problems like you discovered after I had a few hours on it, so this is what I did to get around the selector stem with the scat. I used a 6" long piece of thin-wall 2" diameter aluminum tubing and squeezed it to an oval shape with enough clearance around the stem to prevent rubbing and enough room for the scat and worm clamps. The scat attached at both ends. I fabricated a mount out of aluminum that attached to the tunnel side cover, dimpled for flush screws. A little added weight but I never had to worry about rubbing through the scat and creating a hole in it.
RV-9A: Under Construction. N161RV (Reserved)
RV-10: N959RV Completed 12/29/2013 SOLD 08/23/2016
"Donor Exempt" but donated through Dec. 2018