It depends what kind of sheen you want. If I remember correctly, the gunze flat has more of a satin sheen to it whereas Testor’s Dullcote dries dead flat. If you go with Dullcote be sure to spray in thin coats. As for Gunze, it can be thinned with their own thinner, 70% rubbing alcohol and I believe water as well. Hope this helps.[:)]
I like to use Gunze flat. It’s easy to use and clean up and because it is water based, it doesn’t affect decals at all. Where as dulcote is a lacquer and can affect decals if it is put on to thick.
I use Tamiya acrylic thinner for thinning gunze aqueous paints, and it works fine for me. I’ve heard you can use water.
Go with Gunze - safer and easier to use, and a breeze to clean up. And yes, they can be thinned with water, which is what Gunze Sangyo recommends in its paint chart (you can also use their own acrylic thinner or alcohol).