I used the 2mm sheet sugested by Tenson under bed on the rails, now as you all know I'm not an engineer so this is the closest to level its going to get. I did a vid of the plunge gauge its a 10 mm so by my reckoning its not that far out now. Sorry for the poor quality I tried it on my Go-pro.

Video

Now to put on a 1/2 in bed or something, source some screws and washers.. etc..