Well I hate to be the Debbie downer, but unless the smell is an issue I think acrylics thin beautifuly with laquer thinners.
I had a happy mistake on my last build with MM acrylics. I could not get them to thin and out of frustration, I poured some laquer thinner in to clean the AB.
Low and behold it thinned wonderfuly, and I sprayed my whole Stuka in that mix. Came out great I think