We make a host of different wells with different options. We too had a thermal breaker but like the NS product they tend to fail before ever detecting the heat they should be protecting against. We loved this concept though. If they can get them to last they are very handy little devices for preventing flare ups.
Bottom line is that if you install a well it needs to be maintained and kept clear of debris. Grate or not depending on whats piling up and what wattage lamp is in the light it will smolder and could ignite. I prefer a completely sealed well light like our Apollo or Apollo Star. The Apollo Star being the best. Our Apollo series well lights cpme with lens options to soften, spread, or Narrow the beam as well as a Hex louver to diffuse glare.