Buda,
Definitely not going too big from a sound standpoint if you want to put out the bucks. I have MS5's in a room like yours. Its not a loft but it is similar size and has 10-12 foot high ceiling. I sit 10 feet away and everything sounds great. Pay attention to how Dali says to position them in their manual. That is, firing straight ahead and away from walls a min of 10 inches, preferably more. Good luck!
Definitely not going too big from a sound standpoint if you want to put out the bucks. I have MS5's in a room like yours. Its not a loft but it is similar size and has 10-12 foot high ceiling. I sit 10 feet away and everything sounds great. Pay attention to how Dali says to position them in their manual. That is, firing straight ahead and away from walls a min of 10 inches, preferably more. Good luck!