Why did I save that piece of broken mirror...?

I save a lot of "good stuff".  At the time I did not know that I was going to need a nice piece of mirror to make a bridge but I know now.

This would be a good puzzler to figure out just what is going on in the picture above, but I'll save you the trouble. The mirror is placed on the opposite side of the chord when sawing to the kerf to get a tight fitting butt joint. This way I can see how close the saw is getting to the chord piece above or below the cut without stopping. Don't want cut to deep and nick the other chord piece!

Above you can see how the butt joint has opened after the camber was put into this chord. This can be a significant gap and any load would not be transmitted evenly through a poorly fitting joint like this.

The solution?

My American pull saw! I was having a great deal of trouble with the saw binding during this process then it dawned on me. Pull the saw instead of push it. I also gave the saw a good coating of bees wax. Mirror, wax, Vise-grips, works like a charm! Tomorrow should lay on the web layers, maybe even start the inside chords.

Puzzler - What ideas can you come up with to improve the process?

Tech Vocab - Pull-saw, Vise-grips,  bees wax, Sawing to the Kerf,  Gear wrench