[?]: Measuring thicknes of rubber on machine calender

[robocro1]

gentlemen

small help will be apriciate

i have project where i must measure thickens of black rubber
i have S7-300 PLC with rs 485 comunication
on allready made machine i have to put 6 sensor that will measure thicknes of ruber plate that comes out form machine ( calender , so called machine )
problem is that i have to measure up to 0,02mm resolution , on black surface that is moving with two sensors ,
( oposite direction of sensor that will give values, after that plc will made calculation and I should have thinknes of ruber )
of coures in ideal world
i use 6 sensor because i have to measure two end and midlle of plate

my problem is
price of sensor should not bee ower 500€
sensors must bee profinet or rs485 and adressable
resultion must be around 0,01mm ( i could live with 0,04 mm )
and it must measure on low reflection ( rubber is about 5-6% )

i have some offers from leutz
ODSL9/D36-100-S12
but still no answer from manufature , could this sensor do this

if you have any sugestion , please help
regards