The quality of that env map could easily generate about 10-15 amazing splat reference images. I imagine that would be more than enough. (?) I'm no expert. I just find all of this fascinating tbh.
Also, I heard that an image2depth process of some kind would help out a lot with the final splat. I forget if I actually read about that - or if just wildly speculated about it one bar night. lol.
The env map itself is GREAT! It does a REALLY good job at the polar parts of the map. It's very impressive.