Ah okay, srry for my late reply, I didn't check on this thread for quite some time. But this is very strange. I really don't know what might cause this, seems you did everything right + you unchecked the default gestures so they don't clash. Sounds maybe silly, but did a reinstall help?
Yeah, I did try a reinstall but to no avail
I do wonder if it's somehow related to the vestiges of a very old install, under Mountain Lion or even Lion, which was really buggy back in the day which I had a little trouble uninstalling iirc. I've got 3 macs, a late '13 rMBP, a 2012 Mac Mini and a 2011 MBA, all of which have the same origin install i.e. all were originally installed from the same TM backup. They all run very well, but I find it puzzling that BTT doesn't run properly on any of them, hence I wonder if they have a shared problem.
Is there some plist file I could try to obliterate or something? I did investigate it I seem to remember, but came up with nothing.