JH,
Yes, that is hot. I don't go for the openner. Too hot for me too.
I like to take my lab out, but not in heat over about 85-90F on dove, less on upland birds. So, I go later in the season and shoot less birds.
I used HiForce 44 for a sleeved LC to hold the barrels together and for the forend lug. It was a 20g sleeved with 28g tubes. I was shooting it without the upper and lower ribs, just the spacers between the barrels, but they were long.