I also have the Magna Shades. They are great for daytime privacy but they can be seen through at night when there are lights on inside the coach, so some type of interior curtain is still needed at night. For any protection from heat, they are of limited use. If parked in a nice shady campground or somewhere the temperatures are mild, they do cut glare, and act as screens if the side windows are down for ventilation.
However, if you park in real heat, with sun exposure on the coach and glass, they do not reduce heat gain through the automotive glass. In fact, the black plastic mesh gets blistering hot in direct sun and transfers the heat straight into the glass which radiates right into the coach. If you need to reject heat gain from direct sun and high air temperature through the automotive glass, you need a cover on the outside that absorbs as little heat as possible, reflective or at least white, with some insulating properties. Placing insulation on the inside against the glass will help to prevent the indoor air from convecting. Unfortunately these measures block view and light completely.
As mentioned by many, awnings also help to shade side windows and coach walls. The double-pane coach windows do help reduce heat gain, but shielding them from direct sun strike improves their efficiency.
