I realize this thread is a bit old but wondering how you got on with tinting the outside of the glass.
I ask because I too have been on a very similar thought journey and believe or not I started with your exact approach. Tint and then protect with PPF.
However I decided this approach was problematic and expensive so moved on to further research the problem.
So here’s where I’m at currently.
There are circumstances in the commercial tinting world where for various reasons tinting the interior glass windows of high rise is impractical and so external tints are used. They are actually more efficient as a heat barrier but carry a shorter warrant, usually 7 years on vertical glass and 5 on horizontal applications, but figure that’s not too bad.
However, these products are designed for flat glass applications but I figure the glass roof above the driver has only a mild compound curvature.
Anyway, long story short I’ve decided to try 3M Prestige exterior on the smaller front glass when I get my TM3 as it doesn’t need edge sealing and is smaller.
Any thoughts appreciated.