If you use your CPU to mine BURST with while mining on your GPUs, you won't have any issues other than that CPU miners are slower so you might occasionally miss a deadline on a "fast mined" block.
The GPU-assisted BURST miners can work as well, but they get a LOT slower when you're also mining something else on that GPU.
Ahh okay that sounds legit, I think ill just go with the CPU for now then, maybe spread out the load between rigs since they're only dual core CPU's