Autoleveller

I'm attaching the board to a piece of MDF using bolts from the Edges,and clip the MDF to the table from the sides of the table. do you recommend different setup, also what should be the perfect Z down setting in general for etching.

Hi, I'm new for PCB milling, I bought Autoleveller to help in milling PCB's, I have a problem where I think the milling bit is going deeper than it should even after running Autoleveller on the .tap file produced by PCB-Gcode in Eagle or does not really etch the board, I tried many values for Z down...