I use a soft wide brush and lay several light coats on about 10 minutes apart and get a glass like surface. I then wait a couple of days and apply the decals. Once the decals are dry I brush more Future and once dry I do pin washes the following day. Testors Dull Cote or Alclad Flat Kote will kill the gloss.
I have tried different psi's, different thinning ratios and different air brushes and always get a pebbly finish when sprayed. Alclad Aqua Gloss sprays really smooth and seals up things so it's a very good product that rivals Future but sprays way better for me than Future.
Yes Future was originally designed for floors but how many things and gadgets we use in our hobby that were originally designed for some other use?
Things like makeup application pads with the small handle which is great for blotting decals, applying weathering or metallic powders. How about those tiny dental brushes that are great for cleaning out the tight and small places in an air brush? Q Tips and their hollow plastic handles have a million uses from cleanup duty, smoothening putty, wiping goofs to stretching the hollow plastic handles over a candle to make your own turnbuckles on WW1 aircraft. How about the polishing sticks used on lady's nails? They work great to sand and polish out plastics.