Looking really nice.
Yes, as John mentioned, a lot of early motors had a Breather gear that was timed. Harley Davidson used the pretty much the same engine case setup and timed breather setup from 1936 all the way up to the 90's (if you can believe it). ...and almost all earlier models were pretty much the same too.
To give you an idea, the breather was a hollow cylinder about 3" long and 1" in dia and had a solid gear on the gear case side (driven by the cam) (Open end of breather cyl faced into crank case). It had a window on the side that lined up with a window in the gear case side when in time. The Breather slid into the case connecting to a pocket in the back of the crank case. When venting, the windows would align venting crank case pressure into the breather (inside the hollow cylinder) and out into the gear case. And then from a fitting/tube into the Primary chain side to mist oil the chain.
I am sure I made it sound more complicated than it is, but you could certainly dumb it down for your needs. I am sure I could come up with some pictures if you need.
Regards,
Shawn