Pre-assemble and check everything for straightness and proper rod alignment. Pay special attention to how the rod ends line up with the piviot studs. Correct any misalignment by carefully massaging the parts until you get good straight alignment and flat seating at the pivots. Also, deburr and polish the metal-to-metal contact spots.
I usually find that most of the attachment points on the z-bar to push rod connections out of alignment and they need to be adjusted by slight bending/tweaking to get them to sit flat and have the rods pushing straight.
It makes a huge difference when completely assembled.
Once everything is lined up and seating nicely, I lube all the contact points with that synthetic based, moly, PTFE, graphite impregnated Disc Brake Caliper grease. I like it because it is super slippery, long-lasting and won't attack plastic or rubber parts. It's great lube for so many points on these old cars.