Steering Column Mount Question

Hey guys,
Having had my car a part for the better part of 8 years, I am reassembling now and for the life of me cannot remember how the column/firewall plate attaches. The attached picture shows the plate and the correct screws for it to bolt to the firewall. My question is: What is correct to use to make up the size difference between the 3 large plate holes and the smaller bolts?
Thanks