I did not get the homer lid yet.
However I did go out and measure all of my pails ranging from 5.0-6.5 gal. Every one of them had a 10.25" diameter bottom and a 12.25" diameter top. Including the homer bucket. My "Ale Pail" lid fits the homer bucket. What varies is the height of the bucket.
So, OP, if these measurements are the same as your new bucket supply you can get a lid at HD for a buck.
Drill a lid in the hole, install a grommet and an airlock and you have a fermenter for under 10$
A little research on google indicates these measurments are common for food grade buckets in that size range.