I used a 2.5mm gasket to lower the crystal on this clean116713 to get the magnification rifht. It comes with a 2.7mm if I recall correctly.
It has the original crystal but you should in theory be able to use a sub crystal but you might add some thickness to it as the sub crystal is marginally thicker than the GMT crystal.
As these are reps and not gens there are variations both in cases and aftermarket gaskets so best practice is to have a stack of gaskets and just try until you get a good fit and a magnification you're happy with.
It has the original crystal but you should in theory be able to use a sub crystal but you might add some thickness to it as the sub crystal is marginally thicker than the GMT crystal.
As these are reps and not gens there are variations both in cases and aftermarket gaskets so best practice is to have a stack of gaskets and just try until you get a good fit and a magnification you're happy with.
