There are many people doing in Lahore in different markets.
Montogomery road has full market for tinting. You can find vast variety from there.
There are many shops in auto market at Samsani road in johar town.
There are shops in Township (at the end of Model town link road)
I saw a couple of shops at wapda town commercial area (PIA road) near makki oil. But not so sure if they do tint too.
There are bunch of shops/studios in DHA offering the same services.
However these tint shops must have the digital meter who measures the VLT, UVR, IRR
VLT is the % of light coming through the glass via tint.
UVR is Ultra Violet Radiations.
IRR is Infrared Radiations.