Using traktor without a usb controller, the use is pretty quick and easy. Just click and hold then drag up or down. In the heat of a mix you want it to be as fast as possible. Up and down, easy peasy.

BT headphones im not sure about, whats the latency like? I think a simple headphone jack setup with the right splitter will be best. Having BT running is more resources too, i reckon it will eat up a bit.

Thanks for all these ideas, nothings ruled out till things are tested.

I cant wait for things to start progressing!