Stewart,
Your BCC is so gorgeous, as is Tom’s, I hesitate to show you my bracket. It’s not beautiful, but has worked well, and is a mark II. The first one (epoxied plywood) was really ugly. I had a scrap piece of 1/4" marine grade Al in Australia and was lucky to find U-bolts that exactly fit the boom gallows posts. I doubled the Al for the U-bolts–perhaps not necessary. Some plastic board built up the area that the OB clamps to. The OB doesn’t seem to intrude on the cockpit seating much (I try to sit there if we have 4 in the cockpit), and the mainsheet isn’t a problem. I turn the lower unit around to face forward–the Tohatsu (2.5HP) seems to fit better that way. Everything on a small boat is a compromise, isn’t it?
Dan Shaula