About a multiple system adding latency:

I thought the fact that you will already have client to server lag, it doesn't matter if you have a minimal bit of networklag apart from 'openers'. But during spamming, the fact you already have lets say, 50ms latency, and suppose your network has ehm, 25ms latency, it will effectively overlap, not increasing the already existant client-server lag.

Well, apart from like I said, the first press on a button when opening dps. Which increase -really- isn't noticable anyhow.