One thing I should mention is that although B&W's specs list their Nautilus 800 line at 8ohm impedance, I was told by another B&W dealer that they measure lower (~4 ohms). Looking at B&W's site, they do show a minimum impedance of 4.6 ohms for the N805s you heard (88db sensitivity).
This might indicate that the B&Ws are slightly easier to drive with the 60wpc of the B60 compared to your current speakers. On the flip side, Bryston's wpc rating is almost always conservative. I own a 3B-ST which is rated at 120wpc and use it to drive B&W Matrix 805s. Yet, the amp came with just over 150wpc from the factory according to the build sheet.
So, on one hand your speakers might be more difficult to drive than what Weez auditioned. On the other, you'll most likely get a little bit more power than 60 wpc.
Maybe I'll swing by Dave at AE on Tuesday to ask about the impedance ratings since I work only 1/2 mile away from his store. Sadly, I've been a frequent visitor to his store and one of the providers of his kids' college funds.