The NWSL gears are all metric, the particular gearbox I chose is .03 MOD. It seemed logical enough to continue with that gear specification. I should point out that my version of the NWSL gear is close, but I may not be spot on, because I don't know exactly what the pitch of the NWSL gear is. I made some good assumptions and may have it, but won't know until I test. Given that my gears will not interact with the NWSL gears it does not matter, however I'd like to know. . . .
Gearotic allows you to work from the gear specification and the number of teeth to create a .dxf, stl, or gcode. Although you can make a printable file from Gearotic, I'll probably use Rhino to design molds. From there I can make rubber molds and cast gears in engineering resin. Gearotic Motion was developed by Art Fenerty, who also developed Mach3, a corner stone of the Home CNC comunity. I love the program.