This is a really straight forward solution. The Rid-O-Mice 2.75 inch covers are perfect for the job. Simply insert the covers centered into the hole vertically. This will leave a gap at the top and bottom of the hole roughly the same as the gaps in the cover's grill. You are all set!
In this case you will want to insert a full length 2.75 inch cover into the hole flush with the bottom of the weep hole. Then taking shears, cut another cover to the size of the gap at the top of the hole. Then insert the cut peice so it fits in seamlessly. Use clean, dry shears and wear gloves and eye protection when cutting and handling the cut peices.