I also use Threadmaster Lite and typically, 2 coats is adequate; however, I put it on kind of thick - in my opinion --- and use a paint brush to flow it around and taper it out to the edges as the rod is turning. There might be some isolated areas of thread still showing after the first coat. Typically I will lightly sand between coats. I did have one problem with Thread master that was not due to the material but was due to how much of part A and Part B that I mixed. I was not mixing enough material each time. I was only mixing 1/4 teaspoonful of each bottle each time - trying to cut down on waste - and this wasn't enough to start the reaction. Once I went to a teaspoonful each - of activator and what ever the other bottle / material is called, it went off quite well.
The Thread Master lite seems to also be easier to use and finish nicer than flex Coat lite