You may wish to experiment a little, but if you are using Mr Mark Setter, you may be able to forego the Future application. Unlike most other decal setting solutions, Mr Mark Setter contains a mild adhesive and in most cases can fill the underlying surface and prevent silvering (this is the usual reason for applying Future before decaling).
Be aware that Mr Mark Setter really sucks down the decals on application (due to its adhesive properties), so repositioning the decal can be a little tricky. You can do so with a paintbrush loaded with some water and float the decal to the required position. If in doubt, try it on a test mule first.