I would venture to say that your cvt parts are still OEM.. The "yellow" rollers are probably the OEM 8.5gram.
i would go lighter, I had a 1000 main spring and ran like 7-7.5 gram rollers in mine.
I hate to say this but NO shop will "tune" the scoot. Fix the light yeah but....
A roller tuning kit comes in real handy to try all sorts of different combo's to find the correct rollers you'll need...
If it ran worse with the box on, then it's too rich. Turn the mix screw back down to 1-1-1/2 OUT.(the range from oem specs)... The panty hose could cause debris to get into the carb alot easier than a open filter
(works tho)
I can try and help with your z since your in my mtns.
(you should keep it instead of sell it though.
Z's are special..
)