If you are referring to the RS-1100 standard version, it doesn't have interchangeable lenses, but is compatible with the Whitney anamorphic adapter. In combination, the throw distance range is 1.86-1.93 x screen width, with 0% horizontal offset, and 40% up/50% down vertical offset, assuming a ceiling mount, and relative to screen center.
The RS-1100 Ultra has interchangeable lenses. The options compatible with anamorphic adapters are: Proteus D (short), Proteus E (medium), and Proteus F (long). The D combines with a McKinley anamorphic for a throw range of 1.20-1.58 x SW and 14% up/30% down vertical offset. The E combines with a McKinley anamorphic for a throw range of 1.63-2.36 x SW and 17% up/39% vertical offset. The F combines with a Rainier anamorphic for a throw range of 2.38-3.58 x SW and 19% up/40% down vertical offset. All three have 10% horizontal offsets.
I lean towards the Rainier combo, since it is a few thousand less expensive and allows the longest throws. At the long end of the range of both lens combos, I think the Rainier is as good as the McKinley.
Hope this helps!