Enamel paint and lacquer thinner

I used a lacquer thinner with enamels (Model Master) once...in a pinch, ran out of Testors thinner. I can not remember the brand to save my life...but it worked very well. I tried again with some generic store brand, and pretty much got the same results as you...guess they're not all created equal! 

So, I make sure not to run out of Testors enamel thinner (big red container).

I use Sunnyside lacquer thinner with Model Masters enamel mixed 2 to 1 paint/ thinner and can say you will get a show quality finish from it. I have been doing Don Yosts method of doing nice thin coats building it up where you end up with a nice final wet coat and it comes out amazing. My local Walmart has it in stock but you can get it shipped online.

https://www.walmart.com/ip/Sunnyside-Lacquer-Thinner/118499640

I have also had bad results sometimes using lacquer thinner with Testors enamels.  I have stopped trying.

However, you can use good quality turpentine or mineral spirits.  There was a shortage of Testors thinner a couple of years ago and I started trying hardware store thinners.  I already had some on hand for cleaning brushes and airbrush. There is some real junk just labeled paint thinner being sold at stores.  As long as I make sure the can or bottle says either mineral spirits or turpentine I have had no problems.

I get excellent results thinning MM enamels with the Testor's red can thinner from HL. I do use LT from Home Depot to clean the AB.

Red can all the way and it lasts a long time.

Most "lacquer thinner" is not thinner at all. It's clean-up solvent. It isn't what an auto body shop would use to thin paint.

I just tried mineral spirits (Klean Strip) like mentioned above and other than the smell I can't tell a difference from the red can Testor's thinner, worked very well.

Try making a wash with the Klean Strip. It will look ok till it goes on and the paint in the wash separates like coffee grounds. That's the reason I switched to the red can.