Maybe these that are available from Autobarn?
For the body grommets, the Porsche ones are NLA but I found they're actually an MB item. I knew I should have noted down the MB part number when I had them out!
Otherwise Sikaflex the gap as it won't be much to take up.
EDIT: Actually I'm a king of grommet anoraks and did note it down.
Mercedes Benz part number 186 997 07 81 at $4.50 USD each
To fit 35mm chassis hole and nominal hole size of 23mm which is the usual OD for No. 8 AC hose.
Since you have thin wall it's only 17mm diameter! Bugger. A bead of Sikaflex is looking good.