Too bad Proffit's in Europe. He hates plastigage. It gets the job done, but is nowhere near as accurate as micrometers and snap gauges. Squeezing plastic is not an exact science, but for the rods on a 216 it will be good enough.
One another note, oil film will cause false readings. I assume you're adjusting the rods with the engine in your truck. I would use some carb or brake cleaner on the caps and crank. Get some thin rubber gloves so you don't leave any fingerprints on the crank. And after you are through adjusting, spray some oil on the crank and caps before re-assembling.
