Running no head gasket is fine if you polish the mating surfaces.
I am almost certain I learned that on MA. Mrrbrr even from the wiki?
Use a piece of plate glass and progressively finer sand paper. Figure 8s, 1/4 turn, more figure 8’s. It’s like prepping fiber optic cable (if that’s something you can relate to?)
It will raise compression some losing the gasket and removing a tiny bit of material when polishing. One less thing to worry about.
Torque is an elusive quantity. I mean, there is a proper number, but it’s not like you’re gonna set it and forget it. Each heat cycle, and all them good vibrations, is gonna work new shit loose.
After new gaskets and stuff, I get stuff what I feel is snug enough to not leak (real great answer; I know) ride around a bit and let it cool down. Things will be loose. Snug it back down. Repeat until you put a wrench on a cool fastener and it don’t want to be any more snug. Aluminum is easy to rip threads out of. Err on the side of caution.
You shouldn’t need thread lock or sealing goo on anything. Especially when you’re tuning because stuff is coming apart and going back on all the time. Those things can be great when you’re “done” so that things will stay put longer. I just make a habit of going over everything with a 10mm socket wrench after almost every ride. Trust, but verify.
A dab of anti-seize on the spark plug is extra security. Fresh spark plug gets 1/2 turn after the crush gasket engages the head. After the initial crush, next time you only give it 1/12 - 1/8 turn.
Just don’t over tighten anything. Nothing on a moped needs ham fisted torque. If it is leaking, it needs new gaskets or seals.