All Gunze paint finish is semi-gloss except when the paint is for tanks, in which case the finish is flat and gloss if for cars (this is usually printed on the label). That is, if you use Gunze thinner. When using hardware lacquer thinner or hudson acrylic thinner, the finish is usually flat, even if the label says that it's gloss or semi-gloss. I think this is because the paint dries up a soon as it hits the surface, leaving no time for it to 'settle'.
Be careful when using the hardware thinners. These melt plastic. So when painting, i suggest you apply very thin coats, especially on the first few passes so that the paint will dry immediately, reducing the risk of 'crazing' the plastic. Dont try to cover the model at one pass. Dont worry if you're using Tamiya Sprayworks when using these hardware thinners. They wont melt the plastic parts of the airbrush.
On the other hand, you wont experience these problems when using Gunze thinner since first and foremost, Gunze thinner dont melt plastic nor 'craze' the clear parts. But I still suggest you apply thin coats instead of covering at one pass.
I've been using the Gunze/Sprayworks (not the HG type) combination for many years and for me Gunze paint should be thinned until it has the consistency of milk (not condensed :-)). The paint is still thick when the mist coming out of the airbrush is 'rough'. When painting camouflage patterns, this should be a thinned down further.
I've tried used Gunze Aquaeous paints. It can be thinned by water, alcohol, gunze thinner and harware thinner. I dont see much difference in using these except that they take a much longer time to dry thoroughly
. About 2 to 3 days, otherwise the paint is sticky and fingerprints may appear 
For Gunze Lacquer, the paint dries hard in minutes and can be handled roughly once dry. Avoid painting when raining or just after. The paint 'whitens' (namumuti). Maybe due to the water content hanging in the air. Funny though, I dont experience this phenomenon much when using Sprayworks compressor..
Mr. Surfacer can be airbrushed. I usually use this as a primer, especially when using silver Gunze No. 8. It covers up fine scratches and leaves a smooth finish. Airbrush this as if using Gunze Lacquers. I usually use Mr. Surfacer 1000. They say it leaves a smoother finish than the 500 and is therefore ideal for use for aircraft models. Note that Mr. Surfacer is not that required before using Gunze Lacquers since Gunze Lacquer has very good adhesion properties, as long as the surface is washed before painting.
oooops.... i think i've written a novel already!
cheers!
BigMan :-)
