My only point was that Shopline is a low grade base. You can do much better. Motobase, Wanda, PPG DBC, BASF Diamont, Cromax, Sikkens, Glasurit, Standox etc. If you are looking for the best price versus performance Motobase is hard to beat. . There are a lot of quality base coats out there. Shopline isn't one of them. Being you are in New Jersey you have access to every quality basecoat made. All probably within easy driving distance.
Being that it's turquoise metallic, what I was saying above really applies. Metallic toners used in Shopline/Omni+ are low grade. They won't match OEM metallics on a lot of stuff. When sprayed they look muddy and not very distinct when compared to a high quality base. Also low grade toners don't cover anywhere near as well as premium grade toners. So your cheap base ends up costing you almost as much as a premium base.
For GM turquoise metallic, PPG DBC would be a good bet. I did one about 10 years ago in that color using DBC. Looking at my notebook that I keep, it's smudged but I think the PPG number is 43276. I can't remember if that's a Ditzler number or if that's a direct number for PPG DBC (only number I wrote down) but if you go to a Jobber they can mix it for you from that number. RM-BASF and Axalta will also have the formula. Euro companies like Glasurit and Sikkens may not.
When it comes to reducers use SPI. It is the best performing urethane reducer I have ever used and it is cheaper than PPG DT reducers (for example) by 25 bucks or more. Whatever brand you use don't use a cheap urethane reducer. All reducers are not created equal.
Only telling you all this because the Jobber rarely does. They just want to make a sale and not scare you off with the cost of premium materials. And on something you are restoring and taking a lot of time and effort on, saving a few hundred bucks is hardly worth the tradeoff imo.