The Teslovak KT88 sound more like a GE6550 in you clip, less warm more 6l6'sh. I have always felt the JJ KT88 bottom end to be kinda smeared and a bit loose when I compared them in my amps, but they fit your Major well.
In your clip the JJ KT88 warmness did lend itself to more pleasant tone kind of EL34 like and crazy enough... it did seem a little gainier. Maybe if was the fullness and warmth bringing it out.
I hear good things about the Gold Lion KT88's but man they are expensive.