Initial Results (just relative to driver’s side, since that’s all we’ve worked with)
1. The left slot (side nearest the front of the car) looks perfect. With the adjustment range built in with the slots, I should be able to get the stud exactly where I need it:
2. The slot nearer the wheel, however, needs moved ~1/4” to the right. I’d normally just hog out the latch mounting hole more, but I’ve already done so and am dangerously close to the threshold around the latch not fully covering the drilled hole, I have it set all the way to the very bottom-right of the slot, and there’s still not quite enough room:
Because of this, we may need to add a little extra material for strength, like this (
@Maisonvi would know much better than me):

Also, I think adding a bottom reinforcement tab identical to the top one would be a good idea, since I’ll be using the lower-most range of the slot for the stud nearest the tire on this side.
No clearance issues with the studs anymore, and with only 3 shims:
Excited for the next step and more updates!