QUESTION 1 thin/clean future/clear...etc with a window cleaner (eg, windex, mr. muscle window cleaner, windolene...etc) these contain a trace of amonia but it is enough to clean the future (and any other acrylic for that matter) when you spray future, add a few drops of the window cleaner to it to break the surface tension.
some people spray a few realy fine "pebbley" coats of future, then give it a quick once over with the window cleaner of their choice, this breaks the tension of the previous coats and creates one super glossy and smooth surface. perfect to apply your decals on!!!
have a read through this thread:
http://www.arcforums.com/forums/air/...howtopic=63929
i have learnt alot from this!!
QUESTION 2:
have you tired spraying it neat? try it on a modle hack or some un-wanted styrene. if it dosnt work, just try thinning it down a drop at a time untill you get the desired results!