There's no reason why a Helicoiled thread should strip-out easily. The thread material is way harder than the aluminum into which it has been permanently installed. Just be a gentleman with the bolt torque and you'll be fine.
IDK about that filter, doesn't look like a whole lot of foam thickness. I'd want it properly-oiled, especially if the bike sees anything but clean pavement. That's not going to play well with duct tape...which won't last all that long in this application even without airfilter element oil contact. You'll do better, in the longterm, with a LH turnout intake or finding a better way to duct the filter to the carb.
Why are you R&R-ing the carb so frequently? As long as the float level is close to spec, the only reason a carb should have to come apart is for a jet change. The aftermarket filter may breathe more freely than a stocker, enough to change jetting requirements but, with an otherwise stock engine, you shouldn't need to go more than 1-2 sizes larger than what it was wearing, as-received. The rest is all jet needle height & idle adjustments.
Move the jet needle c-clip to the lowest groove. If the engine goes into rich misfire and won't rev-out at wide-open throttle, your main jet is big enough. If raising the c-clip cures the WOT rich misfire, you have the correct jet size; if not, it's too big already.
