In your opinion, what products are the best satin/flat/gloss clear coats...What do you use...

Future for gloss and currently Testors Acrylic Clear Flat, but this sometimes has issues with fogging things. Until I find something better, that's where I'm at. I know that Vallejo makes a satin that I have heard is good, but have never had the opportunity to try. Cheers.

If I use future, what do I use to clean my airbrush with...I can vaugely remember reading somewhere that you can use windex...what do you recommend?

Flush well with windex then water. I usually run both through twice, two windex then two water. Seems to work ok but it might be worth while to take apart and clean after you use future, especially if you are using flat clear in rapid succession. What are you varnishing?

Dragon Panzer IV A

You don't need to use varnishes unless you are using them over decals. I use a light coat of clear flat just to knock down the sheen on some areas but have found that my oils do not usually make things glossy, save for my oil and fuel spills. Michael Rinaldi has been using little to no varnishes for a while and he claims it works really well and is much cheaper. His work speaks for itself, so it might be worth a try when you have a chance if you are finding it hard to find varnishes. Cheers.

The new Vallejo Polyurethane varnishes are very good. Matt, Satin and Gloss. Mix about 50/50 with their AB thinner and spray.

Humbrol has flat, satin and gloss varnishes, well enamel. and they don't turn yellow with age. just kind of hard to get hold of unless your willing to work with the little tins .

In the United States, I use a certain set of artists varnishes. See a local art supply store. Blick is the online big-gun.

The company is called GOLDEN. Literally the best acrylic paints on the market. More importantly they have varnishes as concentrates you dilute the crap out of - I have one 12oz bottle of concentrate that I've used maybe 100ml of in years. Dilutes with water only. They have many mediums like airbrush medium, retarder, flow-enhancer - I use a combo of those in paint but they recommend not mixing mediums with the varnish. The flow-enhancer doesn't seem to make it mad.

They also come in spray cans, little pricier but they are automotive not hobby sized.

ADVANTAGES: The deadest flat you've ever seen, dries in literally seconds. Totally odor free and far less toxic than the enamel/lacquer varnishes. Buying in artist quantities far more economical than hobby quant. No bottle of lacquer thinner for 30ml should cost 3.99 or varnish rattle can 7$. Just saying. The concentrated varnishes for the 12oz size will run around 12$ for a lifetime supply. I can verify they are friendly to Vallejo model colour and Air, Tamiya and Testors Acryl. They are even UV protective.

DISADVANTAGE: You nearly convert all your paint products to this company. (No I don't work for them )

I switched after twice I got a major mess from Vallejo matte varnish due to to AB tip accumulation -> spatter -> orange peal -> repaint.