The angels I have are scalare. I think you are referring to altums, which get MUCH larger. They are similar in their color pattern though.
I keep my community discus tank around 82-84 degrees. When I have juvies that I'm growing out I keep them at 86. I don't mess with the pH, which is around 7.8-8.0 and the GH is 300ppm. They are doing excellent, just not breeding for me as I planned. That's okay though because I see them as more of a "pet" than my other fish. I like my angels and shrimp but I only keep them to make some money to pay for my "pets". My discus are very friendly and will eat out of my hand. That's pretty common. I also have several fish that allow me to "pet" their dorsal fin and a female that doesn't mind being held believe it or not LOL. I don't do it often, mainly only when I show people my tank. They are like "WOW, he just petted his fish!"