'Cuda, I'm in the process of getting "billet" hinges made for the Dart, I should get them back from the fabricator next week. I found a web page that gives the equation and has a picture of where to measure etc. Weird story, I was going to reconfigure my stock hinges. I went down to my fab guy so see if the small amount of machining had been done and he tells me he has a friend who runs a CNC machine and does trick stuff on the side. Long story short I should have the new hinges in about a week and the I can take all the measurements to figure out the shocks. I'll have to convert everything to metric units but that's no big deal.
The web page, for gas strut calculations, if you are interested is:
Gas Strut Calculator: Calculate the Force Required for a Gas Strut
As soon as I set up the hinges, I'll send along some pictures too.