your H would be a 1940. Here are a couple of sights with H info:http://www.farmall-h.com/http://www.tractordata.com/farm-tractor ... all-h.html
You have a mixture of wiring. Since you do not have a regulator with an L terminal, there should be a wire form teh amp meter to one side of the light switch to provide power to lights, and possibly ignition, if it is a distributor rather than a magneto. To tell you more about the wiring, I need to know where the F lead on the generator is connected. That is what controls the charge rate. Without a regulator, The light switch would normally have 4 positions, L (low charge), H (hi charge), D (Dim lights), and H (les dim lights).