One of two: Advice/ tips on exhaust extension for Saito.72. Asked this in Q/A forum, no response.

Two of two: How short can the nipple be attaching the muffler to the engine? (Saito .72)
Does it matter? I would like the muffler inside the cowl as much as possible. Will this cause an overheating problem? I'm new at 4 strokes, & know they produce a lot of heat, and open to any comments..

Thanks!!!

Allen