I'm with Sheerider. Supertechniplate 32:1 with no failures that were oil related in any two strokes. I run that shit in my weedeater also. Smells good like your riding the trails. Takes the suck factor of weed eating down a notch
Pull the carbs and clean them real good. Inspect the needle and seats. Clean the seats with a q tip and toothpaste. The paste kind not the gel kind. The set the floats per the manual. Off the top of my head I think it's 20-22 mm
Yes the hose needs to be there. It's pulls fuel from the choke circuit in the left carb and feeds it to the right carb. That way you don't have two choke levers. If the hose isn't there it can/will idle and run like shit. Replace the hose and go from there