The incandescent was an example. These will be constant voltage.
Within your lamp you have three or more dimmers. Dimmers (typically an SCR, DIAC, TRIAC or Varsister) produce heat, often a lot, as a byproduct of controlling the voltage to whatever produces light (incandescent filament, LED, etc.). The least amount of heat produced is likely at 0% intensity? 100% intensity is likely very low heat as well. What we need to know is what is the worst use case? What settings will cause your GU10 lamp to produce the most heat and thus be most likely to fail due to a fixture not allowing adequate heat dissipation?
IOW, what fixtures can we know will work reliably and which s/b avoided for someone who will use one of your lamps?
In this case we are looking primarily at two fixtures; Halo H36TAT and Halo H38ICAT. My guess is that the H38ICAT will work better since it has a larger space for heat to dissipate within, much more surface area to act as a heat sink, aluminum surface which should conduct heat better, and no paint.
The H36TAT is smaller, has less surface to dissipate the heat, and is painted which I believe will lessen it’s ability to dissipate heat.
The questions; are we correct in our assumptions about these and is the difference something that will make a realistic operating difference and so worth the extra cost?