This one's probably "common knowledge" but wasn't for me. Perhaps it will help someone else?
TIP # 2040A:
One of the "fun" parts of using a "bolt and barrel nut" is getting the barrel nut in position to screw the bolt into it. Once you drop it in the hole it becomes tricky to move and get aligned with the bolt threads. THAT's where one of those little ciruclar EARTH MAGNETS comes in handy - again. Epoxy one on the end of a dowel that'll fit in the barrel nut hole. Drop the barrel nut in the hole, slip in the dowel with the magnet and you can control the barrel nut nicely.
diagram posted to alt.binaries.pictures.woodworking for those who get it better if they see a picture.
"Real Workbench" progressing again after a few months of procrastinating. Finally am well into building the top.