You can use standard 5W-30 motor oil in the crankcase. 1 quart. But you may want to play around with different oils to see what works best in your tranny (other wieghts of auto oil, auto tranny fluid, straight weight oils (84 or so), and even specific 2t tranny oils like Honda produces)
Keep your mixture at 32:1 for fuel : oil.
As for tweaks- you should visit
www.pingertalk.com