Logitech MX Master reversing Horizontal Scroll

[thenewlinuxmint]

I have pinpointed my Logitech MX master's horizontal scroll wheel to "activate" mouse buttons 6 and 7 with the help of xev, yet neither of these will actually reverse the horizontal scroll direction:

A. swapping 6 and 7 in .Xmodmap

B. telling .xbindkeysrc to activate b:6 when b:7 is pressed, and activate b:7 when b:6 is pressed

Since neither of these actually swap the horizontal scroll direction like intended, is there another way I should be trying?

[thenewlinuxmint]

bump? horizontal mouse scrolling is still reversed :/

[thenewlinuxmint]

Another bump. Surely there must be some other MX Master users on Linux Mint? Horizontal scrolling is backwards