lol i know you're probably mad at me still from the other thread but i thought i would give you my 2 cents since i've been in this situation before
i had a doctor's note (legitimate, real doctor everything) i took a fix it ticket to court thinking with the doctor's letter thinking i could use it, this is where the tricky part is. the note needs to EXACTLY SAY that you MUST have tint, (and i hear even if it says that it might not hold still). my note said something along the lines of something like he HIGHLY RECOMMENDS that I have tint on the front windows, that still didn't hold up in court and i was slapped with the ticket
now as for legality, what VTE is saying is correct, 70% is the darkest you can go in california for FRONT windows, back windows it doesn't matter and no cars (talking regular mass produced cars here) come with front tint darker than that
good luck
http://www.tintcenter.com/laws/CA/