White top (only) is safe and would look very nice. I'm a HUGE Custom Two Tone fan (i.e. non-white factory two tones), but 72 did not offer an option with dark green as one of the two colors. 1970 did have a med green/dark green combo, however both were metallic paints. You could mimic the 70 combo, but with non-metallic paints for a unique look. That was a 1970-only combo by the way, the 71-72 Custom Two Tones with any shades of 'green' were combos of the olives with each other and yellow. I'm not suggesting you should go with a factory two-tone approach, just outlining what ol GM did and they did have one and only one year wherein two green (non-olive) shades were used in the Custom Two Tone scheme. 70 paint codes were 562 and 563 and were mirror opposites of the med and dark green metallics in the Conventional Two-Tone pattern only (i.e. roof and main body different, no change in body color below the belt line). 563 pictured below - 562 swaps the colors. Anyway, as you can see below, the color difference between the two greens is minimal - not nearly as obvious as the non-metallic dark green would be with a med green. Another option that folks don't always consider (all comes down to personal taste though) is a black roof. I think the only GM version with a black roof was 565 (black over hugger orange) - which is a personal favorite. A custom truck with black roof can be pretty cool. Since you mentioned flake... depending on how "custom" you're willing to go, your current paint with an added lace & flake & panels (ala lowrider) roof would look pretty cool - or perhaps even a 70's panel/pinstripe graphics paint job on the roof only could be kinda neat. Might look hideous but it'd be fun to do - and you can always paint over it if you don't like the end result
