First thing would be to remove the pinions. They are sometimes quite well rivetted, so this may involve turning away some of the rivet or being willing to sacrifice the wheel (it could easily be distorted beyond use in punching the pinion out). Then you need to compare the hole in the wheel you want to use to the diameter on the pinion that will be pressed and rivetted in. If too big it gets tricky, you'll need to sleeve/bush the hole very securely. I would open the hole further, then chamfer both sides, make the bush with an undersized hole, then fit it in. Swage the bush with a convex punch in the hole from both sides, then a flat punch that is larger than the bush. The idea is to deform metal into the two chamfers on the wheel. Finally flatten and clean up. Now open the hole to receive the pinion.
If the hole is too small it's easy, just open it up and press/rivett the pinion in.
I have narrowed down the glass for my Roamer Vanguard to the 311802 on roamers chart shown below as X7311 but am having trouble selecting the correct replacement from the many different ones on the cousins site, can any one point me in the right direction please as there isnt a cross reference for this number I can find.
The current glass has a silver coloured metal ring fitted inside and has the following dimensions
OD = 30.60 mm
ID = 27.95
Height 4.34 mm
Thickness = 1.22 - 1.26 mm varies over the surface of the glass, the middle being the thinnest