No worries, more than happy to help out! Someone needs to wave the flag and hand out some native info while Stella and co aren't replying as much :slfg:
Hmmm, well, it depends where he got his information from as to whether the research he carried out is any good or not... there are crays in the tropical areas of the world, which would happly live in warmer conditions. I reckon some "yabbies" in Australia would probably be happy at warmer temps.
When talking about Koura from NZ... they might survive at the higher temps, but life span would be shorter, and they wouldn't be as happy or healthy. All the research I did prior to getting a Koura said "lower than 20 degrees C" as a rule. DOC website, Stellas book, this forum, field "tests" and several other NZ sources were what I utilised during my research phase.
In terms of getting my temp stable as possible.... it is open topped (with a grill so Mr Cray doesn't escape), has poly on back and sides to insulate, and during summer windows are always open in house and ice bottles are always on stand by. Haven't had to buy a chiller for this set up... but I might get a chiller one day instead of having to fret about the temp on a glorious hot day in Auckland
Hope this helps, and if you need more info, let me know.