OK EBM,don't ask me why I am posting this,but what the heck....
First off you cannot possibly be crossing over at 47K(that is the "loading" not the crossover point).
The crossover point is in "Hz"!.....You already have a speaker that goes down into the "probably mid 30's" in your room,but I have not been to your home in a long time(no plans on coming anytime soon,but at least you deserve some decent input).
Anyway,aside from the fact that from what I remember you don't need the Rel,you might as well get the most from it...a damn good sub,if you know how to voice it.
First off(and you should have read the Avalon manual, when you owned the Eclipse more carefully,as it had all the necessary info about different bass systems,and how to employ them in specific rooms)....
You MUST set the crossover point "just below" the speaker's roll off.Or you are going to get an overlap(which you probably have,regardless of what you perceive now).This overlap of bass frequencies will kill the subtle inner details and dynamic shadings that the Mini definitely has in abundance....Don't get "so" involved in bass that you forget about this!!
So,from what I know about your room(having been there like a million times)you should be crossing in NO HIGHER tan "maybe" 32 hz!Even 28 hz,or 24hz is not a stretch!
I kept lowering and lowering my crossover point until I settled on 24 hz believe it or not,because I came to realize that the sub should ONLY come into play on rare occassions,and should not make it's presence known....OR you have it set too high!
Next,the "gain setting" must be LOW!!I had mine SO low that it would have been about a 1.5 on a scale of 1-10.
As to "placement"....I hope it is NOT too close to a corner or wall!!!
It works best when it has room to breathe!
In your room,it should be almost touching the "back" of the right channel Mini!...BUT,it should have about 20-24 inches from the side wall,and at least that from the back wall!
Also,without going overboard(you like to do this,but I'll still save you money)...call Paul at the Cable Co and order the dedicated Rel speaker cable from XLO.It costs only 200 bucks and is excellent,You don't need a pricey cable here,but the standard one sucks!
Put a Cardas XLR cap/cover in the XLR hole too,and run the sub on a quiet line,preferrably one with A/C regeneration.
You should be set,now,but don't read any more into this other than an Audiogon post...That's it!
Good luck...and good bye!