For doo that you need to edit json file like this:
...
this it will add 2 worker / 1 device in M-0 Mode Be ware it depend by what algoritm it is use
...
Thank you for explaining this.
However, I tried it and although it works, it doesen't seem to yield a higher hash in total.
Each worker push about half the hash, but when added together, the total hash is noticably lower than when running a single worker.
I'm just mining Zcash (since NH was hacked) for fun, using a single Nvidia 1070 GPU, and i7 CPU.