Yes I would use the tamiya dark metallic blue backed with black. Test it on some scrap lexan to get the coats between the two to your liking.
Pactra used to have a dark blue but they have been discontinued. Might be able to find a can somewhere. Only other option is airbrush and probably the best option other than getting the abs shell and use tamiyas TS line of paints. More choices. There is like 10+ shades of blue.