I can't really give an authoritative answer on that, since I have yet to use XF-86. But, if it behaves like the other Tamiya acrylics, I'll take a stab at it. I have kind of a "different" way of mixing my paint, since I like to make sure I get a complete mix. Before my Tamiya paint goes in the airbrush, I like to transfer it to a small paper dixie cup using a party straw that I cut in half to use as a pipette. After using my Badger electric paint stirrer, I'll put 1 or 2 straws worth (I dip the straw in the paint to bottom out in the bottle, and then put my finger over the open end) in the cup. Then I use a small, glass syringe to get thinner from one of my many thinner bottles to transfer to the cup. For Tamiya acrylic bottle paints, I've been using 99% aviation grade isopropyl alcohol as a thinner. The ratio that works best for me with that is 0.5-1.0CC of thinner to each straw "pipette". Then I mix it in the dixie cup with a wooden skewer before pouring the contents into the color cup of my airbrush. To be sure I have a good mix and spray pattern, I use sticky notes to make a couple of quick paint shots before moving to the model.