finger(s) + thumb swipe

Hi - does BTT implement the multitouch algorithm or is it relying on the underlying MacOs API to raise multitouch events? If the latter, is there API support for thumb + N finger swipes and taps? I'd like to recreate the Fingerworks gestures that I'm used to from my Touchstream keyboard and the thumb is used quite a bit. For instance, the "undo" keystroke is mapped to a thumb + 1 finger swipe up. "copy" is mapped to a thumb + 1 finger tap. I'm new to the MacOs world but so far it looks like the touch system only recognized thumbs when involved in a pinch/spread motion and otherwise can't distinguish between thumb + finger and index + ring finger.