Terry, once the craft vinyl (Oracal 651) is cut, do you make any attempt to dissolve the adhesive prior to installing on the metal face? I can see on one hand where some tackiness might be good in that it stays put, but then maybe the opposite when you remove. Are they reusable? The cumulative gear backlash during throttle variation is a really good point. I'm still not clear on your mitigating procedure though. Was the test fixture somehow variable that you could tweak the center to center gear distances right? And then once satisfied, you somehow measured resultant shaft centers & replicated these using DRO to the real part? In the test fixture do you measure play gear by gear, like hold one gear, wiggle the the other, adjust... then proceed down the line? A fixture for testing the 40 tooth gears was also machined to verify the meshes and spacing between them. Its design was small subset of the gear tower and was also used to tweak the end mill parameters for the bearing fits. These three gears also turned freely with minimum backlash at their theoretical spacings.