I'm looking to rescape my 10 gallon tank. The vision I have in mind is of a field of DHG Belem, with a planting of some stem plants (particular ones I have in mind are Rotala wallichi, R. macandra 'Japan Red', R. 'mini', and Ludwigia senegalensis) on the left side of the tank. There'd be a border of downoi/some small crypt and some rocks in between the stems and the DHG. The fauna would be a school of green neon tetras (Paracheirodon simulans) and possibly some zebra otos and RCS/CRS.
With the mentioned setup, would a light or dark colored substrate and background look better?