Did some work on solvents to see what the costly MIG solvents were and found something neat. (“Thinner for Washes” is a mineral spirit. “Pigment Fixer” I didn’t identify but Tamiya A-20 or even alcohol will do the same thing. Not knocking MIG here: their products are good and they deserve their success. Whether there’s that much difference between one pigment or another, I’ll let others decide.)
Because I’ve been having trouble with tide marks when doing washes or “dot filters” with oil paints I checked in with the local art store. They sent me home with Odorless Mineral Spirits (OMS). These are not the same thing as “low odor” and certainly different from hardware store mineral spirits. They’re much more highly refined and many artists prefer them to turpenoid use with oils. Any mineral spirit will work with enamels. (This stuff is not made for acrylics.) OMS is made to evaporate more slowly which very slightly slows the drying time, but not much. The result is a product that is almost literally oderless (no small thing - I don’t like mineral spirits) and are very gentle on the surface: excellent for washes and dot filters. I know that some big companies make it for the home and it may be fine. However considering how little you’ll use, you could spend a couple of extra dollars and get stuff made by artist paint companies. In the US the fine Gamblin Company makes Gamsol "100 % pure odorless mineral spirits (OMS). I bought a 16 oz can for $11 and it will last a few years. (Smaller bottles are available.) In the UK, Amazon sells Low Odour Mineral Spirits made by the venerable French paint maker Sennelier. Well worth a try.
Eric