Need Advice for Armoured Crystal

[musicsnake]

I come across to replace the crystal of a 7734 chronograph.  What make it special there a printed chapter ring  which fits inside the recess of crystal before inserting into the case.

I am thinking of a high dome crystal such as Sternkreuz ATCH, fitting diameter OD332/ID320.  For this purpose, tension ring will be removed and fit in the chapter ring.  I understand the crystal size may not perfectly fit these two dimension.  Should aim to find the right ID, then OD can be grinded to reduce without much difficulty. 

To find the right crystal, the easiest way is to get know of the OD/ID relationship of Sternkreuz ATCH/ATCG (otherwise the OD of the crystal and tension ring).  I hope you are able to help to minimize the trial and errors.

[clockboy]

Personally I would just replace like for like.Or just polish the old crystal and refit.

[musicsnake]

The old crystal is cracked on the edge, and I am looking for something like for like.