If you are trying to stay below 6K, then perhaps you may need to change your mindset of using OTL's with a pair of Maggie 3.6's. For a beefy enough OTL to create the dynamic swings, and loudness to make these particular speakers sing and swing, I think you are going to be out of your budget. A few suggestions made here for OTL's seem to be way out of your price range, and the few that are close, may not supply all of the power you require. I do not know about you, but I like to play my music at real volumes, not as background music, so having the ability to play louder is important to me, along with the ability to explode dynamically when necessary.
Generally speaking, most users on the forum suggest matching amps to speakers, the Maggies are no exception. The trend in the forums for Maggies seem to suggest high current and beefy power supplies, something you are not going to get with smaller wattage OTL's. I am sure that the Zero's may aid in some cases regarding matching impedance and ohms, something I would like to experiment with, but, how do you get around for the lack of power and or reserves necessary to make music come alive with small power supplies?
If I were you, I would experiment not just with OTL, but, with other options, such as hybrid and push pull.
If you are dead set on an OTL solution, then please evaluate and provide us with your findings regarding dynamic range, explosive power, and how loud you could play without sound degradation before the amp ran out of power.
It would be interesting to hear some feedback of users using lower watt OTLs with this particular speaker and how loud they play them.
Ciao,
Audioquest4life