My advice is don't mine with the newer PascalMiner 0.2. For some reason you can't find any blocks with it or you find very little compared to the older proxy miner by Volks. Either that or I just got extremely bad luck within the last 24 hours/
But you can only mine with the older R9 280X / 290 / 270x GPUs with that program.
How do you run the 2nd rig using the volks miner? Will the proxyjar in the 2 rig fetch/send data outside of the wallet?. The miners will have the same name, wouldn't that be a problem?
I just use the proxy on every machine, easier that way but you can probably point to your main proxy on the other rigs, I haven't tried.
If you do this keep in mind you might run out of noonces and resubmit the same work if there are too many workers on each proxy since it splits the work among the server.