I have already assembled the camera far enough to test and can confirm that the shutter speeds above 1/125 are all a bit slow at 6ms. I'll do some more testing soon and will update the post with correct times as soon as I have the camera up and running.
It was already a huge win to see the shutter operating! Before, it always showed error 20 on the display, but now it's firing perfectly!
As soon as I have those curtain times figured out, I'm off to machine a new advance gear
Thanks to everyone for the suggestions and help so far.