I've done the last couple of my kits this way, that is using Future on the decaled areas only. They were Academy kits, so I initially attempted this out of necessity only. But it worked well. When I airbrushed MM Dullcoat over the entire model, the finish appeared uniform. The only time coverage didn't look so good was when I brushed the dullcoat on. Airbrushing it seems to do the trick. If it has to be hand applied, make sure it is very, very well stirred. That's worked a few times when I placed decals on some interior locations (cockpits, etc.). But it's been a long time since I've actually 'Futured' the entire model before dullcoating it. Hope this helps.
Bob