The gap at the front footers is 3.5mm. The rear footers are worse as they currently have a smaller 2mm gap. If the Nobsounds require a larger gap I’ll add one spring to the rear footers which will probably get the gap up to 5mm.
When I first installed the Nobsounds, they have a large gap between the top and bottom aluminium piece but a member here advised to get them as close as possible. Check out the thread at the Tech Talk section.