the best way to apply thermal paste is to use as little as possible since it doesnt transfair heat as well as metal.
but thats tricky to do and you gotta make sure the install is 100% fine and not angled at all...
what most mfcs do is use thermal pads, which is what this is as well on the 470s and 480s... its a 1mm thick pad which is a lot easier to install...
if youd use more thermal paste it might just run out at one end, a thermal pad cant... why they used such a thick pad idk... i think somebody at nvidia thought they need it to fill all the gaps between the heatsink/heatpipes and the gpu shim... but thats stupid... you sacrifice efficiency where it matters, where the heatsink and gpu shim make contact, for having better but still very bad contact between the gpus shim and a gap between the heatpipes which can be 1mm deep...