Tinting options, fastback cuda rear window?

Hey all, I'm replacing carpet in my cargo area ('69 cuda fastback) because the color faded badly after 10 years. So I'm thinking this is a good time to tint the rear window. I'm not looking for dark 'limo' look - would be happy with factory A/C glass level (my glass is original, non-tinted type). Mostly looking to limit UV damage and maybe keep car cooler in the summer. I've never done tint, do you guys recommend having it tinted at a shop, or is this a good DIY project?
I believe the rear glass is already tinted from the factory. Unless you had a/c or ordered tinted glass then the rest of the glass was tinted. With the curvature and size of that glass I'd have a professional squeegee and cut that on. Laying on your back while doing that, I know me personally I'd waste more time just crawling in the back.