You could also set the speakers up on the short wall. With the NX-Oticas and separate sub towers, the subs would be almost against the side walls but with open baffle you can get away with that.
Each orientation has it's pluses and minuses. Since it's a dedicated room you can try each configuration and see which you like best.
For overall sound quality and enjoyment you will prefer the NX-Oticas & OB subs to the studio monitors. That is provided you like the open baffle sound.
Mike