Crystal Height Measurement/Classification

[GreyProtocol]

I'm working on repairing an Elgin pocket watch (size 16s) that, among other things, has a broken crystal. Enough of the crystal was left that I was able to measure a diameter of 41.87mm and a dome height of around 1.8mm. I've been able to find plenty of resources to translate the diameter into a Linge size (18 9/16), but I haven't been able to find anything that will translate the height measurement into a height scale. It's from a hunter case, so I'm finding that I should probably choose a height of 7 or 8, but is there any resource that translates directly between dimension and scale? I'm leaning toward getting a 7 if I had to take a shot in the dark, but I'd prefer to be more sure.

[clockboy]

The standardized conversion for a ligne is 2.2558291 mm (1 mm = 0.443296 ligne), and it is abbreviated with the letter L or represented by the triple prime, ‴. One ligne is the equivalent of 0.0888 international inch.
 

However crystals are not sold in ligne but in either millimetres or inches. The height is not critical.

[oldhippy]

53 minutes ago, clockboy said:

The height would be critical it it had been a half hunter. 

 

[clockboy]

2 hours ago, oldhippy said:

 

Thanks I didn’t know that