I saw the announcement for the new pro Shapeoko a few weeks ago and decided to sell my Shark cnc. I may not buy a pro but I know I don’t need 2 cnc machines when I have an XXL Shapeoko. I demoed the machine with my l bracket and let it go with it. I like to work in the center when I can. These were from Myers Woodshop plans. I already had the project saved. The one with slot I already had and do not use much. Wish I had deleted that one and made two of the ones with 5 holes. Hind sight is always 20/20. I could just make another but I will do that someday just not today.
The holes are .31 inches so when I place it I use jog to get the L bracket square to the router and tighten it down. It is occasionally removed but mostly stays in place.