I think 1 bar is WAY too much pressure! Any significant pressure and you will get 2 problems;
1. The water will spray and not fall in one vertical drop.
2. At high speed the display is over too quick and it's better for the drops to fall slow.
I was thinking about 0.5 to 1 PSI, just slightly above atmospheric pressure with the main goal to be to keep the pressure constant to give constant drop size and velocity.
Also it's worth looking into "laminar water fountains" as the laminar flow will fall as a neat stream with no sideways spraying or misting.
It's an interesting idea to mix stuff with the water but first I would explore the level of performance that can be achieved with plain water. People might want to walk through it etc.