I am continually fascinated by the intricacies of the RV-12iS kit. Like this, for example. This is a brace (I think) for the firewall shelf (RV-12 parts don't have names; just numbers). There's a bracket that goes on the other side here and aligns with the center of the engine mount bracket to which it's also riveted.

Like just about every other hole in this kit, LP4-3s are used EXCEPT for one (OK, two, but work with me here): a CherryMax rivet is used on the most aft and middle hole of the engine mount bracket (closest to the camera here).

I have no idea why, but it's fascinating.

Anyway, I riveted the brackets to the firewall shelf as directed, then prepped up the two main bulkheads/brackets/whatever. The drawing noted to insert the forward rivers for the engine mount bracket from the inboard side (there's an overhang that prevents you from doing it from the bracket side) and I did that on the left one but didn't see the part in the instructions where it wants the manufactured head on the engine mount bracket side and so they'll inserted from the inboard side (the thinnest piece). I thought about drilling them out, but that would be stupid.