Do a plug chop....that is,kill your ignition as soon as you hear the pinking noise and before releasing the accelerator pedal.This will give an idea what your mixture/combustion is like at the precise moment the noise is evident.Do this with new plugs if they haven`t alleviated the problem initially.If your old plugs show a lot of carbon build-up then this will be an indication of the state of piston crown,combustion chamber and valves.Worn valves/guides can sound noisy coupled with glowing carbon deposits which cause pre-ignition leading to associated rattles and strange exhaust pulses.

It`s the higher rev range where you might end up burning a plug out/holing a piston so doubt if you have much of a problem with your initial rev-up symptoms as you have described,unless it`s drinking fuel.Providing you service the engine regularly and it is not allowed to overheat I wouldn`t worry too much,even with high mileage and burning a bit of oil,as long as you keep oil&water topped up.