Dual vs single sub

I am probably gonna get a Rythmik F15HP after I get my Preamp situation squared away. Although I would love to buy 2 subs, alas, I cannot. I think I would rather buy one very big, powerful, tuneful sub than 2 smaller, weaker subs for the same amount of money. I assume I could get great sounding music from my 2-channel with 1 sub. Especially since I would only be using high level inputs and running the mains full range and only using the sub to fill in right around 40hz and below. I know that placement would be more important here, so I might do a sub crawl, but I am a bit nervous about it since I really only have 1 place it could fit while still having acceptable WAF - in the corner of the room just to the right of the right main. Hopefully, that position will suffice.

   As far as my understanding of psychoacoustical bass principles and DBAs are concerned, I think of Duke as Mr. Miogi and he's showing me how to wax his car.

Mr Miyagi? Really? And after he said these are not the subs you are looking for?

For all you people planning subs on a limited budget just buy the first one and add another when you can. For point source speakers 2 subs will get you 90% there. For you panel jockeys, Magnapans and electrostats you are going to have to shoot for 4. 

I have made dipole subs using 6 drivers aside. They do not work. Even with huge amounts of power and room control you can not get 20 Hz out of them effectively. IMH experience the best performance comes from sealed, enclosed 12" subs Q @ 7 with Room control and a high powered class AB amp damping > 500, the higher the better. The only difficult variable is the enclosure itself which ideally should be infinitely stiff and heavy. 

Oh, by the way I use dipole speakers with sealed subs and have absolutely no problem matching them up