This is one of my personal 1:1 favorites and the next one to build. I like your color choice and your paint finish looks good as is. What colors are you using for the interior ? The engine looks fairly accurate but I question the general shape of the kit's valve covers. The creases on the top of the valve covers I remember were shaped a little differently, but they were the standard 389 cu. in. and that could be the difference.
Another Meguiar's product to try is called Plastx clear plastic cleaner & polish. It is designed for taking scratches out of plastic instrument covers and tail lights. I'm sure it would work on head lights also. I used it on an old Monogram '64 GTO molded in red. I trimmed the mold lines as much as I could with a #11 blade followed by fine sanding sticks and a 3200 sanding pad. This leaves you with just a little polishing and maybe some waxing.
It maybe that Testors is doing colors that can be done in just one shot. Candy colors are usually dependent on a base coat of a high metallic silver or gold, and a transparent color coat of what ever shade you're going for.
Everyone needs a place to go when they feel the need to get away. It will be different for everyone. For myself its building models. I'm fortunate that I have late model automobiles needing little more than normal maintains. It hasn't always been that way as at times in the past I have spent far to much time in the garage.
I enjoy detailing the engine compartment the most. Over time I started with plug wires and thought it was great, then came heater hoses and battery cables. Each build I would try to do more and more. Got the fuel lines down pretty well and then I started into the throttle linkage and just started getting frustrated trying to cram all that stuff under the hood so started backing off a little. Doing dash board instruments are still enjoyable but unless its an open car you just don't get to see it. Seats and door panel detail is rewarding but again its just to hard to see. I respect the efforts of so many builders that get into the brake and fuel lines, but I don't see myself ever going to that extent. The exhaust systems are something that I do enjoy with the challenge of guiding the exhaust around and thru the frame and differential. I still think the paint and exterior trim is the most important since it is what you see first and is the part of the build that receives the most scrutiny. I should thank all of the detail obsessive builders for all that I have learned from watching how and what you do. It has enabled me to improve my builds greatly.
Interesting bit of useless information from the photo after GM had redone the car. The Project X started out as a 210 model as seen in the old photos. It looks like when the car got redone they put the Bel Air trim on the top of the rear fenders, IE the chrome trim running along the top of the fin. I think the original build with the hood "gun sights" removed looks better also.
The "Snake" mentioned a red Dodge made me think of the song about "The Little Old Lady From Pasadena" in her shine red Super Stock Dodge. I think that Dodge used that song in a lot of their adds around 1962 thru 1964. That could be an easy build.
I will usually paint the headliner and door sills when I reach the primer stage but not the final sanding of the exterior body. After that dries I'll mask off the exposed interior and paint the interior of the body and inner fenders with a flat black where it will be seen and then masked . The wheel lip area and maybe areas around the bumpers that would be body colored are left uncovered. Then proceed with the body work and paint. After the exterior painting and clear is finished I'll remove the interior masking. There is usually a very thin ridge of paint around some window opening that has to be removed, but other than that it usually works well.