Yeah after BT KK I tend to go with 66K. Either way it doesn't matter, BT KKK ends with a mid kick, 66K is a mid kick, and 3P+KK is a mid kick. Not really much mix up there, and most people actually counter mid kick if you don't do the BT KKK full string.
Still, 3P+K has 2 other options, so it's...