Completely agree with jaap...
I'd wet sand with 2000 and then polish. Trying to polish out 1200 grit sanding marks will take a while and require a rotary with proper pads and skill, which maybe you have. I'm familiar with PPG/Shopline but not familiar enough with Meguire's products to make a specific recommendation. If you want to talk Menzerna, you'd be looking at their Power Gloss product for 1200 grit scratches. PM or e-mail and I'd be happy to try and help. As Jay mentioned, I'm a dealer for both Adam's and Menzerna so let me know what questions you may have.
- Darryl