Hi DEW,
I have used Digger Bucket Washers, which are available in assorted thickness packs and diameters on flea bay (in the UK at least), along with a suitable needle roller thrust race from a bearing factor. The bearing comes with a couple of hardened facing washers, so you use the Digger Bucket Washers to make up the pack height. Does the biz, but may take a a couple of trial assembly trial to get it right.
Cheers for now
Doug