RIO offers their Game Changer Skagit Max in 725. As for warm conditions I've no experience with lines that are marketed as warm or cold use products. I can tell you that a normal Scandi line works just fine at zero degrees so I would expect it to work just fine at 98 degrees too.
Check with Steve Godshall. I know he makes heads for the Meiser 909 rods, which are short two handers designed as boat rods for big game fish like muskies, GT's, and Tarpon. I think the grain window on those rods goes up to 650 grains, but I'm sure he can make one heavier if you want. I don't know about his lines and tropical heat, but you can ask him. I've used his lines in Hawaii with no issues, but that's no where near as hot as typical tarpon water.