Nick informed me that the wirewound coating rod we used in the AZO workshop last month is the RDS #130 'gapped' rod. Theoretical coating thickness is 11.7mils, well outside of the 5 to 7mil range that was recommended by Ron. I asked Ron about this and he guessed that the #130 rod was chosen mostly because it was available and for no other particular reason. RDS has many other rods available. Their #56 rod is listed at 5.04 mil coating thickness and the #80 rod at 7.20 mil.
Here's a link to the RDS download page for specifications: http://www.rdspecialties.com/techinfo.html
Of course, a glass rod wrapped in tape might work just as well and cost a lot less.