340se vs 340sec for mains

This is my first post, but I've been shopping on line for a month and the only negative thing I've read about Ascends are their so good that their going to be a bit revealing on bad music. Now I just need to decide the best package so I can make an order and start the wate. MY room is 17'6" x 22'6" x 9'6" and I have a denon 3803 amp. Is that a large enough room to take advantage of the 340s vs the 170s for mains. If it is I'm planning on 340s across the front and 170s for rears. The problem is the fronts are going to have to sit on top of built in shelves that are on the left 35" off ceiling and 25" of ceiling on the right. It seems like the 340sec layed horizonally and tilted down would work better for the mains. On the description of the SE they claim exceptional horizontal dispersian, would I loose that on the SEC. Are the crossovers the same? On the package deals there is no place to put in SEC for mains. Do you think the price would be the same as a pair of SE in the same package? Thanks Bob

The only difference between the 340SE and the 340SE center is the use of the exbac in the 340SE center to compensate for the baffle effect of being on a tv or in an entertainment center. I'd get Ascend's advise on what the best solution for your set-ep.