Ron,
I stand corrected. I use a similar jig; mine has stainless steel set screws (so solder won't adhere) to move barrels precisely side to side and/or up down ever so slightly, while measuring that movement with separate micrometers. Once the settings are achieved, I take away the micrometers, and set screws hold everything in place, and I solder. Seems to me that heat would alter precision of your micrometer set-up, but if it works, it works!