Revell Aqua Paint thinning question

I only have 3 of their acrylics and have so far used one. I was told they're rather thick and I found that to be very true. I've yet to air brush any so I have no idea how to thin them but brushing straight from the container resulted in excellent coverage without any brush marks. The one I used is black, silk matt 302.

I bought red, yellow and white, the worst colors to spray. I will thin them about 1 thinner to 2 paint. Seems to work alright. The Revell is OK IMO and seems to stick well but I like Mission Models better for acrylic.

I used three of these paints on a GB last year & thinned them with de-ionised water until I got the usual thin milk consistency, I don't think I used any actual measurements.  I was happy with the results, though.

Edit: forgot to say I airbrushed these, maybe thinning to a slightly thicker consistency may work with the hairy stick?