When I had my 5's, not the 5A's, I used that rear firing tweeter and liked it, much to the chagrin of my dealer, JohnnyR and Richard. My room had three walls of glass and for some reason the rear tweeter ameliorated some of the issues with the glass. Go figure. I would say try it and then decide if you like it. Good Luck!
Vandersteen Question
....just wondering if anyone uses the rear firing tweeters on the big Vandersteens. Richard designs these with equal phasing....doesn't that rear speaker ruin things?