Getting grease gun onto u-joint zerks

[mancad]

I was fortunate enough to get a great 1968 C20 Custom Camper survivor from the original owner; less than 57,000 miles. While doing routine maintenance I tried to grease the three drive shaft u-joints. I could not get the grease gun coupling to clear the yokes welded on the drive shaft. No problem I thought, just jack up both rear wheels (posi) and turn the shaft until there is clearance. Still no access. Upon inspection, there is no straight shot onto the zerk. The whole drive train is incredibly heavy duty. The large yoke extends into the path to the zerk. There is no room for a universal or even a tiny coupling. The only way I can think to work around this is to remove the u-joints and install 45 or 90 degree grease fittings. I also makes be wonder how they were ever greased in the past. Anyone else seen this?