Yes, the Hobby Lobby hardware does look good. The 2nd from the left looks the best. It would place the connecting point closest to where it needs to be to be "perfect". And of course, it's proven that perfection isn't an absolute necessity.

That hardware actually will suit some biplanes better than others. The problem of making the connections right angles is most affected by the stagger of the two wings. Lots of stagger causes the most problems. Very little stagger and there is almost no problem. Very little stagger and the 3rd from the left would work. The other thing that contributes to the problem is the size of the ailerons. Longer chord ailerons permit you to move the connecting point away from the hinge line. The farther you can go, the less problem.

I would suggest that y'all seriously consider using the regular horns and slotting them into the ailerons. It's a very simple, quick, and easy job. And it gives a much stronger structure. The epoxy strengthens the balsa around the horn. The other methods usually wind up crushing to a degree, and if the screws aren't perfectly tight, the base will work loose.

All it takes is an Xacto and epoxy. OK, and I use a small drill. I slice the base off the horn. Using the drill bit in my fingers, I put some holes though the horn where it will be buried in the aileron (the glue through the holes links the aileron's wood through the horn). Use the Xacto again to slot the aileron. Apply some epoxy into the slot and press the horn into it. Wipe the squeeze-out away and it's done. It actually takes me less time to do that than to get the bloody screw holes lined up and the screws through the stupid horn flats. They never line up and the screws never want to thread into the flat.