To be honest, too much choice is a burden. Secondly, concealing the wall is no good at all and my advice would be to avoid doing it altogether. Third, testing colors on the wall is not good idea and should be avoided as they react to one another and to the existing colors of the wall itself. Instead, paint a square of thick wood card to try it out.
Put them next to the colors you want to combine them with e.g. boards, window frames and the next rooms and see how they work.
Colours often look different from the color chart. They mostly look stronger because they are on all the walls, but after a few days you get used to it.
Here are some sample images: