Future dries FAST, after all it is a floor polish, however it doesn't completely cure in a short amount of time. You can apply the acrylic wash pretty soon after the coat of Future, however getting off the excess might cause some problems if the Future hasn't completely cured. I usually leave it overnight and haven't had any problems, however humidity and temperature can have a big affect on drying time.
But .... just to prove to myself that it could be done (and I wasn't real worried about how the finish looked) I tried something Saturday. I shot some parts with Tamiya Fine Surface Primer, and let them dry in front of a fan for 30 minutes. Shot some acrylic over the primer, and let it dry for about 10 minutes. Sprayed a heavy coat of Future on and let it dry about 15 minutes. Added some washing, let it dry 5 minutes, and shot a coat of acrylic flat. About an hour from start to finish, but as I said it was just a test to see what would happen. So far nothing has flaked off or melted through, but I guarantee nothing is dry at the bottom of that stack