Hello USA, I'm Bob Carter, I've been associated with the Sandbach CAUC team in UK for over a decade. This is my first post on this forum; I'll look in from time to time & if I can offer advice or the benefit of my experience I will :)
FWIW Peter (whs) has been "greenpowering" even longer than I have....
Yes we get all our sprockets laser cut. The results are accurate to about a thou and cheap (little more than the cost of the material) - for example we have a full range of motor sprockets from 14 to 30 teeth (yes, every one!) and that little project cost us less than $50. We use a commercial laser cutting service on the industrial estate where I work and they charge me commercial rates for the jobs. I'm sure every neighbourhood has a similar local facility. I email them a dxf or dwg file of the profile & pick up the results 2 to 4 days later.
FWIW we have standardised on 8mm chain. The 3/8" is similar pitch but much chunkier so the weight of the sprockets & chain is all a little more (the sprockets have to be fatter material). the smaller 6mm chain is no longer roller chain so it's a touch more lossy (we did run with that for a while).
WHen designing a chain transmission remember that sprockets with 12 teeth or less become comparatively inefficient.