No problem, he has already succeeded. By setting the tool clearance to 60mm his machine is already 20 times more rigid than someone who thought 200 mm might be necessary for some unlikely job in the remote future. He can chuck a sacrificial 20mm MDF sheet over the bed and get an even more sensible 40mm clearance when the penny drops. If you are not engraving there is no point having a clearance greater than your tool sticks out the chuck.