You aren't going to get below ~9ms input lag chain anyhow even with a crazy low latency monitor.
Yeah this is off topic i know but i had 12ms total roughly there is nothing in this and 9ms. The 240hz Gsync works out at two 4ms frames at 8ms then you add on the pc lag 1ms and mouse lag 1ms and keyboard lag 1ms and then the monitors 1ms G2G.
Though my mouse is 2000hz 0.5ms so when i get the Gigabyte 0.5ms monitor it would be 11ms.