Hi 007
First may I ask can your finger nail catch the scratch? Your using a fine cut cleaner it will remove light oxidation ,stains, scratches etc. your in the right direction to move up to #5. After using #5 you can follow by #2 . You don't have to do the entire car with #5 just the areas...
I have been working with Gtechniq C1/EXO combo's for the past couple of months. I sealed a Black truck with C1,after C1 I waited 72 hours to apply EXO without any haze or high spots... I have used Cquartz products also. C1/EXO are my personal favorites. Check out the video's I have on Facebook...
I have to test the product first on panels Before I go spray it on a customers car. I believe this product leaves a satin finish. Maybe a good product for undercarriage applications.
I have used both products on clients cars, In my personal professional opinion Gtechniq is what I would go with. I have photos on my Facebook page. Mixon Custom detailing LLC.