Jets
Silver solder works best but is harder to use and you would have to flux the peice to be soldered. A regular fluxed solder should work just fine. Motorpsycho is right, too rich won't hurt the engine. It may foul a plug and produce a little carbon build up, but otherwise your engine will be fine. Too lean is very dangerous for an engine. I'd rather have a 2 cycle engine belching a little smoke than none at all.
You can buy smaller jets, Motorpsycho knows where, and they just screw in. I think the standard size jet they come with is 70mm. I would start off with a 68mm and see how it runs. Good Luck,
Big Red.