my mtrack configuration (MBP 15 Late 2014)

10-mtrack.conf

# Copy to /usr/share/X11/xorg.conf.d
# or /etc/xorg.conf.d if the above doesn't exist
# Not tested if this makes a difference but included nonetheless 
# Intended to use with my 50-mtrack.conf

Section "InputClass"
  Identifier "Multitouch Touchpad"
  Driver "mtrack"
  MatchDevicePath "/dev/input/event*"
  MatchProduct "bcm5974"
  MatchIsTouchpad "true"
EndSection

50-mtrack.conf

# Copy to /usr/share/X11/xorg.conf.d
# or /etc/xorg.conf.d if the above doesn't exist
# Refer to the official mtrack readme 
# (https://github.com/p2rkw/xf86-input-mtrack/blob/master/README.md)
# to tweak your settings

Section "InputClass"
    MatchIsTouchpad "on"
    Identifier      "Touchpads"
    Driver          "mtrack"

    Option "FingerHigh" "15"
    Option "FingerLow" "15"
    Option "Sensitivity" "0.043"
    Option "AccelerationProfile" "4"
    Option "ConstantDeceleration" "0.1"
    Option "AdaptiveDeceleration" "2"
    Option "VelocityScale" "1"

    Option "ClickFinger2" "3"
    Option "ClickFinger3" "2"
    Option "TapDragEnable" "false"

    Option "ScrollDistance" "150"
    Option "ScrollUpButton" "5"
    Option "ScrollDownButton" "4"
    Option "ScrollLeftButton" "7"
    Option "ScrollRightButton" "6"
    Option "ScrollCoastDuration" "500"
    Option "ScrollCoastEnableSpeed" "2"

    Option "SwipeClickTime" "0"
    Option "SwipeSensitivity" "1200"

    Option "SwipeDistance" "1"
    Option "SwipeLeftButton" "1"
    Option "SwipeRightButton" "1"
    Option "SwipeUpButton" "1"
    Option "SwipeDownButton" "1"

    Option "Swipe4LeftButton" "9"
    Option "Swipe4RightButton" "8"
    Option "Swipe4UpButton" "11"
    Option "Swipe4DownButton" "10"

    Option "ScaleDistance" "300"
    Option "ScaleUpButton" "12"
    Option "ScaleDownButton" "13"
    Option "RotateLeftButton" "0"
    Option "RotateRightButton" "0"
EndSection