no sir jee, I mean 0%. This percentage is actually described by the level of light that is allowed to pass through the tint. Not by the blackness, sadly our roadside tint wallaas describe it in the opposite. Refernce pic attached for u.
and as for reverse thingy, well, what I mean is k don't park u car where u can't move unless u reverse the vehicle. In this way, someone can park his car right behind urs and ask u to step out of it. U can do nothing but execute his commands. with ur car in a sweet spot, u can always slam the gas pedal and scram from a situation going dirty.
I always keep a distance of more than two feet from the car ahead of me so that I can move away easily if it stops, like some taxi mehr khans die on signals when the driver switches them off to save fuel I hope u get it now.