Tamiya acrylics are not true acrylics, they are acrylic lacquers. I thin tamiya with Mr hobby Mr leveling thinner. This thinner has a retardant in it to keep the paint from drying too fast.
It shoots just like enamels with this thinner and I can shoot for over an hour without any tip dry. This thinner will also work with Mr hobby aqueous paints, Gunze Aqueous hobby color and may work with other acrylic lacquers.
Even though testors is killing enamels, there is still plenty out there, stock up now while they are cheap before they reach floquil prices for old stock. Testors enamels have a long shelf life. I have bottles of testors enamels that are over 10 years old and still good.