I was playing with a 7123 yesterday, my first venture into quartz fiddling. Getting the gear train bridge on and all the staffs in their bearings was a royal pain in the arse. It took me two hours (and I did swear a bit but carried on for the learning practice).
With basic tools only I got all the cogs and stepper rotor lined up as best as I could and lowered on the gear train bridge, put in the screws and did them up loosely just to hold things in place and then using strong magnification pushed each staff into its bearing with a slim needle. I could only do this visually so good light and magnification is essential.
Also it was necessary to remove the circuit board and coil for access.
I think I prefer manual/auto watches