I think my rod bolt stretch gauge and tool are Pro Form, it works great
I bought it from Comp Cams 10 to 15 yrs ago, the dial indicator measures in .0001 increments. I set it at zero on each bolt and then torque the bolts, I sneak up on what the rod makers suggests on torque and find the middle of the stretch, if I can. In other words if they want from .0059 to .0064 I shot for .0061 to .0063. If they suggest 65 Ft. Lbs. I start at 50 or 55 Ft lbs. and go up in 5 lbs. increments
I do see differences in the rod bolt lengths (.00010 to .00030) as well as what torque is needed to get them to stretch to the length I'm shooting for, even on the same rod
I guess it might be faster to remove all the bolts and wash the rust stopper off of them and then premeasure the lengths and then try to match them up on each rod