Harry,
I'm appalled that you assemble your bicycles without cleaning the seat tube and fork steerer with a deburring tool! Sure, you've got the right brushes for the job, but your toolbox is, IMHO, woefully inadequate! The best tool for this use is, of course, Campagnolo's #10 tool, made from Tullio's toenail trimmings and available in five sizes - big through pinkie. These were precise little devils, though somewhat rare. The hardness was somewhat variable as well, depending on the age of the tool, though I never actually did a Rockwell test. I've found these tools are acceptable for use on French steerers and bikes built with metric Reynolds 531, though the more appropriate choice would be Lucien Juy's version of the Campy. They don't come up on Ebay too often, though.
Happy frame stroking!
Derek Vandeberg
Tongue in Cheek, I mean Bigfork, Montana