I gotdecent quaity mirrorsfromebay which are much better than the smalstock ones,sure it was an 8mm thread,most are a standard size and wijust screw in.
The cdi cut will only give 1-3mph increase, the boss around another 9-12mph,taking it to around 42-43mph if algoes well.The jet change wont give you any more speed but will stop you running lean and possiblly damaging the engine after you do the smooth boss and get upto riding at WOT (42mph). Some are fine on the 80 jet but most usually go up to 82,i did anyway.
Good idea to keep it restricted till he gets used to it. I kept mine like that at 1st but i ony lasted maybe 3-4 wks before i felt it was too slow. Once hes experienced enough he prob wil want the litte bit extra top speed.
You can get visors on ebay too that fit,both tall and shorter length ones,or bike and scooter shops or onine scoot shops wil do them.
Heres my ebay mirrors,cost me about £9.50 delivered to the UK,i think. My home made visor is in the pics too
http://www.kymcoforum.com/index.php?topic=5166.0