You can use the calligraphy pen in the pen holder on here. It definitely will draw and I have proven that. The medium is what you need to figure out. You can even use paint pens. We use it to lay out borders with a marker and then paint it by hand.
If you are painting A small area then you could widen the size of the sled and essentially make a huge donut. Then mount everything floating over the middle and mounted on the edge. That would give you more area to move and not touch your painted area.
I don’t think you would be able to use gravity due to the angle. However, you could use something pressurized. Look into pressurized paint mediums. Maybe even an airbrush?