Mark, we're planning 10-ish for the meeting. and thanks for the Rodney link. I just found them about an hour ago, but too late to have them there in time for Saturday's meeting.
Pat, I had been thinking along that line, too. After giving some thought to what would keep the bolts from loosening in our original idea of a threaded plate, I thought of welding capture nuts onto the plate. The frame is higher than wide, so a plate could be cut longer than the width and almost as wide. Turn it on edge and slide it into the window cut in the side of the rail then lay it down. It wouldn't even need to be welded in.
Maybe we can get the cradle in with just 3 bolts temporarily then do the final solution later.