I use a deflector on my Alpha trainer, and it does a great job of keeping oil off the plane. On my Four Star, I have actually run a plastic tube from the muffler and tie-wrapped it to the landing gear. I took out the muffler baffle to compensate for the added resistance, and it works and sounds great (OS 46LA).

I am putting a Super Tigre 45 on my current build. Those mufflers are pretty bulky. I would expect to get some resistance from it if it is tipped too far. I am planning on a deflector for that as well.