Just found transmission information, a forum post said that the Haynes manual for the NC30/35 lists NC21 and NC24 specs in the back of the book. Well, my dad just so happens to have that Haynes manual, so I finally know my gear ratios!
Stock, with 140/70/18 rear tire(Haynes seems to think a 130/70/18 is stock. It may be, but my bike has the larger size tire.
45 mph: 4453 RPM
70 mph: 6927 RPM
Same as above but with a 40T rear sprocket instead of the 45T stock.
45 mph: 3958 RPM
70 mph: 6157 RPM
With a 36T rear sprocket...
45 mph: 3562 RPM
70 mph: 5541 RPM
To compare, the NC30 with stock gearing is at:
45 mph: 4487 RPM
70 mph: 6980 RPM
Off to gearingcommander to add another bike!