"I swapped out the glass too, but will have to go back to the old crystal as the tension ring does not quite make the dial."
If the crystal is acrylic and "the tension ring does not quite make the dial' means the reflector is not quite wide enough...GS makes a line of acrylic armored crystals (press in type) that have extra wide reflector rings. They are called Wide-Tite (WT).
Sizing example...if the crystal seat in the case is 30.0mm, you need a 30.1 or 30.2mm crystal, probably 30.1mm. The wider the crystal seat, the bigger crystal OD you can get by with...a 33.0mm crystal seat will usually accept a 33.2mm OD ET or WT armored crystal.
If a 30.1mm crystal seems to be a little bit loose in a 30.0mm crystal seat, you can apply a thin coat of epoxy or crystal cement to the crystal seat before pressing the crystal in the case to hold it in place.
W-T example:
https://www.esslinger.com/gs-watch-crystal-wt-wide-tite/
GS brand ET and WT crystals are the same except for the wider reflector ring on WT types.
Specify reflector color when ordering.
'White' = chrome.
'Yellow' = goldtone.
GS round crystal types:
http://www.ofrei.com/page810.html
I never found the Waltham watch mentioned above.