Interior and Upholstery 88 Vert quarter window gears

I have an 88 vert that I inherited. It needs a ton of work but it is bone stock one owner with 134K miles on it. I need to fix the broken plastic gear bushings in the motor. I was told by someone to replace them with ball bearings and they will never wear out. All I could find was for a Bronco. That site said to use 11mm ball bearings. Anyone heard this before? Can you verify if 11mm is correct?

Thanks