Helldog, I would not necessarily blame the FCG or the whole FCG. Could be a combo of things.

Clint, the 60% is a touchy-feely thing. You could do the testing with the hammer spring removed, that would make it easier or easier the first time to familiarize and understand the process.

A person could make a dial-indicated measuring rig but I don't think it's necessary. Due to the pull-each-other-into-engagement geometry of the hammer / trigger relationship, anything over half ought to be good; more is better of course.