First, I would like to say Thank You to everyone who posted and I’m very glad to hear the positive comments, and thankful for the opportunity to stay busy building these products.
Regarding amp selection, I generally like to use the speaker’s sensitivity, impedance, and distance from the speaker that the end user will sit as well as the average peak decibels that the client listens at to gauge what amplifier choices will work. If there’s at least 6 db of headroom over the peak listening levels (which equates to double the power to both speakers), then I consider this a safe margin.
That said, at listening levels under 90 db at 3 meters from the OP's Legacy speakers, the Super KT SE is more than adequate as it can provide peaks of up to 100 db from them. The Transcend push pull absolutely would work as well and have headroom to spare for even louder listening levels. It also sounds stellar- more similar to the Super KT SE than different really, however with single-ended you get just a touch more inner detail and realism- and I do mean a touch, but it’s still there. I did also design the Transcend Push Pull to have more of a "single-ended" signature to the sound, while gaining more power than a typical SET, so if there are any doubts that the 20 watts using KT150s will be adequate, then the Transcend Push Pull would have an extra margin of power and very similar sonics. It’s that trade off between slightly better sonics vs slightly more power which is the major difference between SE and Push Pull in my experience.
Best regards, Aric