Hi-Gloss and Crystal (Krystal?)-Coat were both clear as water. I never saw a big difference between the two.
Any of you guys remember the red booklet Floquil had regarding their paints? I remember reading it in the 1970s, and it just being a fun read with the about pigment particle size, how to paint, top coats, etc. Ah, good memories.
I have used straight lacquer thinner for over 30 years for thinning and cleaning and have never had a problem. Even Floquil thinned with lacquer thinner and stored lasts quite nicely.