Re: Poweder metal or stone for voids
Dave Paine
A topic worthy of starting a bar fight. 
Like so many topics in a hobby, there are many different preferences.
My experiences.
a) I use CA for thin cracks where I am trying to make the wood more stable to prevent tearout and where I am not intended to add tint or substances with the CA. Be aware CA is brittle compared to epoxy.
b) I use epoxy for thicker cracks where I want the strength of epoxy to hold the wood together. I often colour the epoxy.
c) If you add anything to epoxy it is best to do a test to confirm that the substance will not impact the curing time of the epoxy.
d) Some tints/pigment do not mix easily with the epoxy. I use Smooth-On resins and the Smooth-On tints which disperse well. I tried oil based paint with the Smooth-On resins and they do not disperse, and so will settle out while the epoxy cures.
e) I have used oil based paint with System Three resin which dispersed easily.
f) Stone and metal will tend to settle as the epoxy cures. If I recall another thread some weeks/months ago touched on the subject with brass and the poster mentioned allowing the brass to settle, pouring off the top and using the settled brass/epoxy. This may be more viscous so may not get into smaller cracks.
g) The folks at my turning club who use stone add the stone to the cracks then apply the CA on top of the stone. They may use several applications to get the crack filled.