I have an hdr cc,but not memor-x model as i actually didn't know there was that model in HDR.
but generally with my hdr model i have found, for horses.it has fit most horses comfortably i have had it on,maybe the exception of a couple that were harder to fit.
i find it a comfortable saddle to ride in compared to my old cheap AP saddles.at times i do feel it puts me more into a forward seat as it has a higher seat then most that would be only dislike though.. i have had some friends ride in mine and they seem to say its a good comfy saddle as well.
im not sure if my post will help you much as its a totally different hdr model,but figuring its by same company it would give you a bit of an idea.
happy saddle shopping