Bret ---
I have a couple of the 90* slotted 'jigs' that I use just like you have shown in your photos....
One of the things I did with my table - was to drill and tap (table is 1/2" steel) various combinations so I can just "bolt" the 90's to the table in various positions. It's fast and I don't end up with clamps for the 90 in my way.
Now - since I consider these "tools" - I just need to figure out what to do with them now that I have 'em.
