The reinforcement plates needed to be drilled to the spar. Here's an outboard one clamped in place prior to being drilled.
Here's the same plate after having been drilled for rivet holes.
Here's the view from the rear of the spar, for posterity...
Here's the rear view of the middle reinforcement plate after having been drilled.
The aileron pushrods actually pass through the middle reinforcement plates. So, you have to cut out a funky-shaped hole for the pushrod. I used a couple Unibits to ream out a circular hole first. It might be hard to see here, but I clamped the plate to a 2x4 and then down to the bench. Drilling through something under the metal keeps the cut nice and clean.
And then used the Dremel (first with a cutting tool and then a sanding tool) to shape the hole appropriately.
Here are both plates, deburred and ready to go. The tool you see here is one of many types of deburring tools. This one in particular is used predominantly on hole edges. It has several different "bits" inside the handle. I don't really know the difference, to be honest. The one on there works fine. By the way, the holes don't look symmetrical in this picture, but take my word for it -- they are.
Next I drilled out the inboard spar doubler plates. These components being pre-punched makes this kind of thing really easy. The holes are pre-punched to something smaller than #30 (1/8"). You just drill 'em out. It takes a matter of minutes. The only thing you need to be careful of is keeping the drill perpendicular to the surface so that the rivets will set nicely. Other than that, this type of thing is trivial.
The rear spars are just about done. I have some deburring to do, a few holes need to be countersunk, and then it gets primed. That'll all happen some other day. I'm wiped.