the EletriCub is built up balsa so Monokote is fine Chillie...
I find the opaque colors do well - sometimes the light better than transparent. With the more solid colors they "glow" more than just shine right through.
More lights is always better - and you need to select a lighter color. The dark ones have a good deal of color added and get very opaque.
I would consider using Nelson/Solite covering. It is lighter and has less pigment (to save weight) and lights have no issue going through those.
Good luck - and remember MORE lights than you think.