Why would one use them with Maggies? I thought they were meant for tube amps that didn't like seeing low impedances such as that presented by estats. Maggies are a nice 4 ohm load and most tube amps I know have 4 ohm taps.
Because back in 2007 I was able to talked to someone in ARC that he was using his REF 110 w/ the autoformers w/ Maggies 3.3 and Apogee Dueta's . Both were very inefficient speakers he said but because of the autoformers the REF 110 was able to drive them effortlessly using the 8 ohm tap of his REF 110. Maybe somebody else in this forum had tried this already?