the ratio you're using is fine.. as for naphtha, smaller pulls are better, and make more of them! like, say, 80-100ml warm naphtha for this amount of bark per pull, and make maybe 5 pulls or so.. this way you can straight away stick it in the freezer without pre-evap (or with just a little pre-evap), and after yielding your crystals, reuse the naphtha for more pulls.. Then the last pull, leave it in the mimosa soup for longer, like a couple of days, and after getting the crystals (if there are still any) from the freeze precipitation, evap that naphtha till the end to see if anything is still inside of it