Tinting them is easy but honestly the i don't recommend the tint from chain stores. If you can find a window tinter that is willing to sell you the material, it's actually not that expensive. The most common are sun-tek and sun guard tints both have lifetime warranties against going purple unlike the ones in the store.
As for the back windshield don't do it in stripes unless you want it to look like a cheap job lol. Just use a heat gun to get the "fingers"(bubbles) out.