But see, here's why your question is above my paygrade (which is none). I wish someone else had chimed in, but nobody has. Here's my difficulty, and why I think anyone would have difficulty -- you're trying to supplement a large dose of potassium when it's plentiful in a range of very healthful foods.
Tinting of front windshield glass to reduce light transmission is not permitted, except for the upper 6 inches of the windshield. For side windows or rear windshield, glass tinting that reduces light transmission to less than 32% or increases light reflectance to more than 20% is not permitted. For SUVs, vans and trucks, the limit is 32% for the driverâs window and the front passenger window only.
Windshield tint is allowed 3 inches down from top center provided that there is no factory tint already there. How dark this will look on any given vehicle, has much to do with the the vehicle in question. Interior color of the car plays a huge roll in how dark it will appear. For instance, if you tint 2 otherwise identical Altima's, one with black inside, one with tan inside.