[popcornmix]

or is it just as simple as this?:

arm_freq=1150
core_freq=600
sdram_freq=650
over_voltage=8
over_voltage_sdram=4
force_turbo=1
max_usb_current=1
gpu_mem=192
disable_overscan=1
hdmi_force_hotplug=1
hdmi_ignore_cec_init=1

The Pi will set the gpu_freq= to Default 250 or 240 if you set core_freq=600 and that's it?

Personally I'd just use this. If that overclock is reliable, then performance will be good and tweaking gpu_freq will probably not result in measurable improvements.