No, you just have a differing opinion on the matter.
As I stated, the temperature issue is IMO, but others have differing opinions on the matter, and indeed, there are hobbyists who are successful at higher temperatures than the 76° you mentioned.
However, I believe there are many more that have failed at the higher temperatures.
As to size of the dwarf H. zosterae, the ID GUIDE states: Maximum recorded adult height: 2.5 cm but I've seen hobbyists state they had ones slightly over an inch in height.
You can probably fit 3 or 4 dwarfs on a silver dollar.
As to tank size, it's better (again, IMO) to have smaller tanks due to their feeding habit of preferring to sit perched waiting for the live food to come close enough to be snicked up. This means that to provide the food density required one needs to hatch and enrich a heck of a lot more brine shrimp than for a smaller tank.
I've had no problems with around 50 dwarfs in a 5g tank.