Normally you would do darker in the back. I have 5% (Limo tint) on the back 5 windows and none on the front, the fronts are already slightly tinted from factory and with the reduction of light coming in from the back 5 the fronts look a bit darker. In Alberta we can't (not supposed to) tint anything on the front doors or windshield. A lot of people do anyway and the police don't seem to bother too much.
If you want to do a tint on the plastic you could try VHT NightShades, works great on taillights so it would probably work on plastic windows.
2013 JKU Rubicon - Commando and 71 Jeep CJ5 (pretty much stock)
Teraflex 2.5" spring lift, Teraflex monster front and rear trackbars, G2 wheel adapters, Goodyear Wrangler MTR Kevlar 35 x 12.5 x 17, Superchips Flashcal, Warn Zeon 10, Smittybilt XRC bumpers front and rear with tire carrier, Metal Cloak Overland Fenders, Uniden Bearcat 980, Homemade side rails. 50" and 20" light bars and brackets.