Today was one of those days that snowballed in mistakes and recovering from them. I started off all fresh and confident that I would be able to recut keyholes in the legs to mount the boosters. I measured marked, made several templates and once I determined the places to cut, I even used a punch to make a precise area where my drill bit would start cutting (using my nice new drill press). Also created a template of the boosters and laid it over the legs to visualize the booster location.
But the most important thing of all went right over my head. So obvious and so stupid that I hate admitting it in public like this. I FORGOT to compensate for the boosters being pushed downward on the keyhole. And that makes all the difference in the world. So where I cut the holes was too low unless I salvaged my mistake and used that location as the absolute location of the boosters (no sliding downward on a keyhole. I doubt I'm the first person to do this and I doubt many people will notice so I simply drilled the hole directly through the leg and used 2" flat head countersunk to attach the boosters using only the middle two booster threads. That's really all that's needed as they're not going to be under any stress. And they both look beautiful. So I compromised a little but so what and it works just fine. I also finished tapping the holes for the other shoulder shims. so horseshoes, boosters, and shims are ready to go.
Towards the end of the day I started getting tired so mistakes began multiplying at a exonential pace. After drawing blood the realization came that it was time to close up the garage and call it a day. Yeah, call it a fun day.