Yes, the proper way to drill and tap cover would be to remove. However, I really do not want to pull cover at this point. May have to down the road.
After much consideration this is what I have decided, unless someone here thinks its a mistake, I am going to pull the cover for the access to fuel pump linkage. It is the cover that has the crankcase vent on it, and I am also going to pull the cover that gives access to the govenor.
I will fabricate duplicates of both covers and add 3/4" steel nipples welded to duplicate covers. I will then attach a 3/4 inch "tee" to allow access to the fuel pump linkage cover and also run a line to the duplicate govenor acess plate.
This gives the oil 2 places to go. If I get on a steep hill and oil starts to back up it will back up to the "tee" and hopefully drain from there. There is only about 3 inches of fall to Fuel Pump Linkage cover but I have about 5 inches to bottom of govener cover. Problem is that the govener cover to turbo is about 20 inches and the slope is not "good". Driving the tractor up a somewhat steep slope could make oil run TOWARD turbo. This is why I will have the fuel pmp cover as a back-up drain.
Does this read as reasonable??