I have some 1000 line left from my DRO project, but the computer ran out of steam in order to use them to the maximum advantage.
The good thing about using Rutex is that they have step multiplier switches on them.
This means if you did use 1000 line encoders on them, and your computer did run out of steam, you could use the step multiplier to reduce the steps per revolution to suit your computer. If one day you got a better computer you can just turn the step multiplier off.
Being outside the square !!!