I know what the fuck you are talking about, I had dropped several hints and right over your fucking head....
Don't you think that if Ebay customers have blown diodes in real life situation, that part of your problem is solved? Now you could measure the range of Tc, to see what your diodes will handle, but real life tells you it has been done...
Regardless, how come not a single 3w diode runs @ 3w? You never answered......regardless of the pertinence, it does matter, since it means you understand how to measure the over-current of the diode.....That IS YOUR TEST RIGHT?????? and you don't have a clue....