help on crystal ref

Hi guys

As said on another post I bought this Seamaster for 170 euros which is cool. Unfortunatly no caseback. The ref may be 166.009. Unfortunatly too the wheels bridge is a 565 insted of 562 which is not a big deal as I intend to keep it for the time being. I may have a 562 bridge in a drawer.
I'de like to change the crystal as it's badly scratch and not original. I can't find the reference and size. crystal opening is 29,7 or so. Some help would be appreciated.
As for the caseback I was thinking of puting a see through casback as the movement is rather good looking.
this may give a nice watch after a few changed parts such as the mainspring, crystal and a fancy strap. The dial under this ugly crystal is pristine.

Correct crystal is 063PZ5140.

Thanks Rendo and Archer

there's a step. the dimensions I gave was the wider one on the edge of the case. So 29,62 mm sounds good for the narrower diameter. I popped up the bezel to remove all the craps sitting between the midcase and bezel.
Does anyone have tried the generic cousins crystals?

have a nice day.