I don't believe Ron is saying that tamping won't work with dense graded stone, but rather that the lifts that you use it with should be smaller.
Would 8" lifts be sufficiently thin for the plate compactor to penetrate with this aggregate?
I've been looking on the forums, and am aware of the discussions that you've had regarding compaction of aggregate fill. The usual recommendation for compaction seems to be requiring placement in lifts of a ranging depth, and then passing over a couple times with some kind of tamper or...
