I went 30% on the front windshield, 20% on the front driver/passenger window, and 15% on all the other windows and rear windshield.
I have the same on my truck and jeeps. I would not go darker than 30% on the front windshield. At night, you can see clearly, no interference.
If you tint, do not go cheap, its worth the money for the Ultimate Ceramic tint. It will really reduce UV expose (98% for 15 % tint) as well as the IR waves that cook the inside of your rig. It still gets hot inside when it is sitting in the driveway, but when you get in and drive, you will find the A/C works quicker, more efficiently, cools even better while you drive because the tint is blocking IR and UV waves.
Ceramic Tint does not interfere with your phone or GPS inside the cab. (I also use a tablet with Onx maps, no issue) If you go cheap with the metallic tint, you will have problems.
Last word, get a reputable installer. I use SunDowner who has done all of my vehicles and house windows over the past 25 years. Remember, you get what you pay for.
If I lived in the North East, probably would not do so, but here in Arizona, its a must have.
Last word, I wear sunglasses religiously. In the Northstar, I have to take them off.