This may not be perfectly on point, but FWIW, I have a Glider medium output and had the ability to adjust impedence on the fly. I went thru values from 47K, way too bright, to 25ohms, way to dark, slow and muddy.
So if you like your system on the lighter brighter and crisper side of neutral go with 600, and for the obverse 200. And if you can't make up you mind go for 400. (FWIW I ended up at 2000 with my Glider).
The problem is that this is a sonic issue not a functional one and unless folks knew what you had and what you liked/wanted an intelligent answer might be hard to come by.
So if you like your system on the lighter brighter and crisper side of neutral go with 600, and for the obverse 200. And if you can't make up you mind go for 400. (FWIW I ended up at 2000 with my Glider).
The problem is that this is a sonic issue not a functional one and unless folks knew what you had and what you liked/wanted an intelligent answer might be hard to come by.