It does vary from scooter to scooter, on my 210 with matched casings and scorpion pipe I run a 125 main jet no other carb alterations.
However when it was run with a modified crank as well it needed a 132 main and altering to the other jets as well.
If the head has not already been altered to reduce compression it may need done as this can cause problems as well.
Just check plug colour and listen for a rattling noise(pinking).
Be very careful if it pinks as its running too hot and may seize.
thanks for the info mark ive settled on a 125 myself for the moment and will try to reduce it a little more when its got some more miles on it