"The part of the rehaut where the crystal sits is very tiny. And you have to find another crystal. Diameter is 29,0 mm."
Just now measured two genuine Rlx cases, 16200 (R serial) and 16234 (E serial). They are very low mileage (with spring bar holes) and have been stored for about 30 years. Both have crystal necks rising 1.02mm to 1.03mm above the case deck with crystal necks measuring 29.48mm to 29.49mm OD where the crystal gasket (sapphire) or crystal skirt (acrylic) mounts.
An oem spec sapphire crystal and gasket or 25-135C acrylic crystal will fit these cases with proper bezels. A 25-22 1016 crystal will also fit them but the ID of the bezel must be cut to fit the thicker crystal skirt.
They make excellent 1016 or DJ project cases (high WR) and I machined the 16220 case to accept an ETA 2836, 2846, 2789 etc. in 1994 or 1995.
The modified case will accept a Rlx 3035, ETA 2836 etc. to make a DJ with either sapphire or acrylic crystal. I had a 3035 with a 'Buckley' type dial in this case for a while back then but sold the movement soon after putting it together.
Catch 22...since the dial seat has been machined deeper into the case making the dial mount higher in the case...when using a dial with applied markers, the second hand may rub the crystal when using a sapphire crystal (this is the reason for the 'Buckley' dial). This is not a problem when using an ETA 2836, 2846, 2789 etc. with acrylic crystal.
There is always more than one catch...
Genuine Rlx 162xx cases are high $$ now and many of the cases for sale are ratty, some ground and buffed to the max, and others rotted out by corrosion.
Typos are free.