The maximum distance from the Tx to PoE switch and from the Rx to PoE switch is 100 meters.
So the maximum distance between Tx and Rx is 200 meters.
Theoretically, 1000 are the most, as long as each Rx unit is assigned to an IP from 65534 IP.
The IHD-410PR might not copy the correct EDID. Please refer the following:

We suggest user to use the same screen resolution to set video wall so that user can get the best performance.
We suggest user do not use the low-resolution monitor to watch the higher quality video source. The screen resolution can only be backward compatible, not forward compatible. So please adjust the video source resolution appropriate for the output screen resolution.
Please refer the steps: