Hi Paul,
Normally, the ideal situation is to print from the RAW image in the camera profile color space.
That, of course, calls for a camera profile, and printing from the Raw.
May I ask what camera you are using so we can check to see if one is available; just curious!

Second choice would be a Tif or Jpg in Adobe color space. It has more colors than your printer can print, and probably more than enough for your camera too.
RGB is fine too. Just technically a little tighter on colors than Adobe.

Prophoto is not recommended due to the extraordinary wide color gamut which can lead to posterization  since other devices cannot cover that wide gamut.


Wiki says it better than I.


The ProPhoto RGB primaries were also chosen in order to minimize hue rotations associated with non-linear tone scale operations. One of the downsides to this color space is that approximately 13% of the representable colors are imaginary colors that do not exist and are not visible colors. This means that potential color accuracy is wasted for reserving these unnecessary colors.
When working in color spaces with such a large gamut, it is recommended to work in 16-bit color depth to avoid posterization effects. This will occur more frequently in 8-bit modes as the gradient steps are much larger.

Hope this helps,
Fred