RE: Trimming Slimline to fit
There is a tubing sold in LHS's that's labeled as something like "tuned pipe connector" or somesuch. It looks like HUGE silicone fuel tubing. One size fits the Slimline pitts muffler pipes. You can see it in use on a couple of my airplanes.
I usually saw the pipes to length so that the cowls can be easily placed or removed without having to dink around the muffler or having to saw gaping holes in the cowls. Most times I simply cut a couple of lengths of this HUGE tubing to at minimum, replace the lengths sawed off. I usually cut the lengths longer to keep my airplanes cleaner. My SkyBolt is almost dry after 6 or 7 flights, the usual number in one outing.
If you notice, one of the pictures shows the tubing with pipes sticking out of the tubing. I wondered about the noise from that particular muffler and whether or not it would increase with the removal of the ends of the tubes. Those tubes have restrictors in their ends. So I simply used the silicon tubing to put the pipes back together. I flew with the ends attached, with them removed, and with extra long tubing without the ends. Couldn't tell any differences and neither could the other flyers. Well, that is, we couldn't tell a difference in loudness. I noticed the short stacks wet the bottom of the airplane so now fly with long silicone extensions.