Sounds like you've had similar problems to me.
I previously fitted a set of EBC green stuff pads, to the front.
They are very expensive, extemely dusty, and only lasted 12 months. On the plus side they way out performed the OEM pads.
My car is a daily driver, but has never been on the track, I suppose I'm a little heavy on the brakes, but not that bad, I'd say most Skyline owners would be heavier on them than myself.
It seems if you want good quality pads their going to cost big bucks and not last very long.
Thanks