The trick to 'em is that the clvis/hiem joints need to be inline and parallel to the ground. They need to act like the hinge of a door. If you get that wrong, even a little, then the car will be hard to align. The struts act to push/pull the bike to/from the car. The car's wheel should be toe'd in a little and the bike leaned away from the car (about 1-3 degrees from vertical). All those adjustments are made when the car and bike are loaded.
Get ahold of Jay at DMC sidecars. He has those plates ready to ship for $150. You'll need to add the U-bolts and threaded rod to replace the lower engine mount thru bolt. I added a couple U-bolts and i can show ya what I did to give the U-bolts some extra surface. Jay can also advise you on any differences between the 1100's and the 12's. He's a really smart guy and has Ben doing this for years. Will save ya a bit of aggravation.
Something else that makes those plates kinda tough to fab is that they have standoffs welded to the back sides. You can see a little of the standoff peeking out of the top of the front mount in the pic above.
A little paint, some hardware, and you'll have solid mounts set up for straight forward alignment adjustments! You'll see what I mean when you have a set in your hands.