Ideal Temp for Mixed Tank

[thermidor]

I have a 40 gallon with a few e's and PP's and 2 strawberries. I would like to know the ideal temp for them; each seems to have a slightly different "range". Am I better off having it skew low or high; for example, would it be preferable to have it at 83 day and 80 night (low) or 85-6 day and 83 night (high)? This is basically the difference of using one of my UTH's.

I am getting a thermostat to be able to control it pretty tightly but would like opinions on what the best settings would be. Might as well shoot for the ideal as long as it's possible!

[wodesorel]

Don't worry about the PP's - they enjoy the high temperatures that the exotics need, too.