As for the type of fuel line for the muffler connection: Easiest option is a sacrificial piece of regular Silicone fuel tubing (about 1" worth) connected to the tygon by means of a short piece of 3/32" or similar brass or aluminium tubing.
Silicone can't handle liquid gasoline, but is surprisingly resistant to heat or vapour, and these sacrificial pieces for me last anywhere between 2,5 and 5 years.
The better your fuel/air mixture, the longer it lasts, and that is not because of chemical action between the silicone and the unburnt fuel, but because the unburnt fuel burns in the muffler and raises the muffler temperature. The better the A/F ratio, the cooler the muffler runs.
This difference is remarkable: The oil I use does not bake on to the muffler, so my aluminium mufflers remain fairly clean,, but if the engine is running rich, the muffler gets hot enough for a fingerprint to burn in and also to deteriorate the silicone from heat. When the mixture (air/fuel) is correct, the silicone remains intact and fingerprints do not burn in. Heck, the latest engines That I set up from new, the header did not even really discolour.

And strangely enough, these really lean (near full stoiciometric) don't even rise cylinder head temperature too much. It is just a guess, but I think that a lot of the heat generated in the muffler afterburning a rich mixture, otherwise gets conducted back to the cylinder head. Any fuel not supplied to the engine, also cannot contribute to heat generation...