I have decided to run off the crank shaft. If I remove the alternator, and machine an arbor , and a new cover plate with the arbor going through the cover plate and seal. I own a machine shop, so this will be some work, but it will address the correct rpms for the pump and should be a fairly straight forward solution. I was considering removing the main drive gear on the counter shaft, but realized this would also eliminate my oil pump, and water pump. Anyway now the normal sprocket shaft can power an aftermarket alternator. Probably crazy, but I think this will work. On a side note I bought this engine used (18,000 miles on it) for a very good price. Although I would enjoy playing with some other engines, they are all very expensive. The Husa would be a lot of fun to play around with.
Remember to leave just enough of the alternator rotor to keep the starter gear and sprag clutch.
By the way, after a good look at the service manual I deduced that if the main and countershaft 3rd gears are swapped on their shafts it will make an overall ratio of 0.95:1 (0.625:1 reversed third gear x 1.52:1 primary reduction), making the output shaft turn about 5% faster than the crank. In any case it would be advisable to remove any non engaged gears in the trans along with the shift mechanism to reduce needless drag and excess weight anyway.
I certainly hope you are looking for a counterclockwise rotation viewed from the generator side of the motor, as regardless of the drive source, crankshaft or countershaft, that's the direction you have available to you if the drive faces the stern of the boat.
Incidentally, getting at the trans is quite simple: to split the cases all you need to do is remove the alternator, clutch and pulser covers, remove the clutch / oil pump drive, any top case bolts, lay it on the head and upper rear mount, remove the oil pan, and unbolt the cases. I'd say an experienced mechanic could be looking at the transmission shafts within 20 minutes of getting the engine out of the frame (Not a problem for you!)