Hello Dave,
I have a pair of Legacy Classics that I have biamped and monoed. I can't speak for the Focus but I prefer my Classics in a biamp arrangment. I used a pair of Adcom 565 monos for about a year and never did really like them as much as I did using 4 channels of a Parasound 805. I have replaced the Adcoms with two 2200II Parasounds and like them very much. Everything just seems tighter and cleaner all the way through the musical range. The amps of which you ask about are all more expensive and considered by most to be superior to the Parasounds so I suspect your results will improve even more than mine.
I have a pair of Legacy Classics that I have biamped and monoed. I can't speak for the Focus but I prefer my Classics in a biamp arrangment. I used a pair of Adcom 565 monos for about a year and never did really like them as much as I did using 4 channels of a Parasound 805. I have replaced the Adcoms with two 2200II Parasounds and like them very much. Everything just seems tighter and cleaner all the way through the musical range. The amps of which you ask about are all more expensive and considered by most to be superior to the Parasounds so I suspect your results will improve even more than mine.