Thanks for the update, very helpful, and I am using powdered bark. I waited a little while and now there does seem to be a distinct, relatively clear layer on top. Really though, there are three layers atm. There's a clear layer on top that's almost definitely smaller than the original xylene added, there's then a brown layer beneath that which actually stuck to the glass and hid the clear layer at first (also the brown layer is probably 3-4 times larger than the clear) and then there's the bulk of the mixture that's still black.
I'm assuming that mixing it really vigorously just caused a ton of material to get pulled into the xylene that will take a while to fall out. The clear layer does have a yellow tint to it now so I'm guessing it worked fine.
I'll definitely be letting this sit for a while as it REALLY pulls more than naptha.