Alexis, it took me a couple of views to understand what you have done here. If I've guessed right, you've made 3- clamps; each using a pair all-thread rods and passing through a pair of identically drilled boards. Tightening the nuts retracts the rods into their respective load spreaders (boards) to provide a clamping action. This is a clever adaptation to produce a purpose-built clamp. I use a lot of things similar to this in my work and often use "pass-through" knobs instead of nuts - in this way wrenches become unnecessary. Also, I have a set of wrenches which are driven by ratchets that allow a rod to pass-thru, they are perfect for use in all-thread rod situations. They're made by Gear-Wrench.
OPG3 Tweak everything!