If you haven't sealed the wood yet, you could apply another treatment of AF, that should darken it. I'd do some experimentation on a scrap piece of wood... LMF stains like American Walnut, Nut Brown, or even Ebony Toner, could be wiped on with a rag to darken. I'd try either of these before adding anything to the Permaly.... Again, try it on a scrap of wood.
I think Permaly would be okay with Chambers Oil, but would let it dry completely before I applied Chambers Oil. Do the strap wood thing again. It's been my experience that Chambers Oil will "eat" bone black, and make it disappear. Hope that helps.
Ed