Welcome to SPCR.
You don't mention which Gainward 560Ti model you have...is it the Phantom or something else?
I'd install both Gentle Typhoons in the front. Can you hear them at 800rpm? If not, leave them as is. If you can, then there are a couple of ways to lower the rpm. Your motherboard comes with Fan Xpert utility. You can try that. There's also another utility called Speedfan
. A third choice is to get a hardware fan controller (Zalman Fanmate 2 or any of the ones that fit in a 5.25" drive bay). The more airflow through the case (without hearing it) the better, as that will in turn keep the CPU and GPU cooler, which in turn means their fans won't ramp as much.
Do you hear the Velociraptor?