The Fine Things are Always Hand Made
The curve of a convex glass crystal is pretty standard and not a concern.
The proper dial bezel is your quest. If you locate one missing the glass, then a measurement will provide the diameter of the glass. Glass sources are on the web.
There are multiple depths and curvatures of convex dial covers but radios with curved round dial covers seemed to only use shallow spherical glass. Clock supply companies carry many sizes of dial covers (possibly called clock glass) in two or more shapes. The Scott Masterpiece dial cover lens is 5-11/16 inch diameter.
Right here. Most sizes are available in 1/16" increments.
You might want to contact Mark Palmquist about a replacement dial glass. He makes both glass and plastic pieces. He has lots and lots of them that can be made up, his prices are really good, and his quality is very high.
Here is his website. https://dialcover.com/
I’m aware of Mark, thanks for the reminder Chris. His work is especially valuable for those one off glass convexities falling outside the normal,clock glass curvatures.