Keep same width of middle column in ThreeColMid layout in xmonad

For my large screen I want to have one window in the middle of the screen and the other (slave) windows on the side of it, like in https://hackage.haskell.org/package/xmonad-contrib-0.13/docs/XMonad-Layout-ThreeColumns.html#g:1 . If I have >= 3 windows opened this is as I want it. Suppose I have 3 windows open. Then one occupies a large fraction in the middle of the screen while the other two are symmetrically on the left and right of the middle window. However when closing one or two windows the master window changes size and position (for example with only one window it occupies all space). How can I configure xmonad such that the master window always has the same position and size when in ThreeColMid layout as in the case of >= 3 windows? I.e. for one ore two windows the remaining space should be padded. Maybe this would help: https://github.com/brianshourd/xmonad-layout-padding . However using this I can only add another layout which does what I want for one window (not for two). However I don't want to change the layout to make happen what I described above.