The block of wood is a cool idea. However, wood will deteriorate over time. Screws holding parts on that are exposed to any force will work themselves loose over time. Tightening the screws up every once in a while isn't going to be enough as the wood material the screws are threaded in to is going to give out, not the screw simply backing out.
For a temporary test, maybe a couple test rides, it would probably work. However, I would not take off on tour with that being your permanent solution to leave on the trek with.
For what it is worth, I have about a 1/2" discrepancy. I started riding back in 2014 with platform pedals and tennis shoes, no toe clips or anything. All my legs did was push. I built up my muscles and tendons to do that motion and nothing in the opposite to balance it out. Long story short, my kneecaps were getting pulled sideways and the one on the left was grinding against the leg bones causing excruciating pain. I spent 4 months in physical therapy over it, off the bike of course. In that time with physical therapy my therapist found the discrepancy and got me on a heel lift.
That $#%ing heel lift was a mistake. It started causing other problems. So I took it out and have never looked back.
The biggest change I made to my riding stamina was to get clip shoes/pedals. They are a bit awkward to get used to, but it didn't take me long. Having my feet fixed to the crank like that is amazing. I can balance out the motion by pulling up on the crank also so it keeps my leg strength balanced.
I do have reversible pedals on my bike - platforms on one side and clips on the other. There are rides I have been on where I have to take the pressure off the balls of my feet and put it on my heels. I can't do that in the clips so I unclip and flip the pedals around. That gives me a lot of flexibility while riding to balance out the wear and comfort.
Last note - don't get too concerned with things being entirely anatomically symmetrical. Do what is right for your body, whether something is symmetrical or not (like the crank length already mentioned). Your body will adapt - just like a new pair of shoes. Give it time and you will adapt.
The hard part is going to be getting all the conditions "right" for your body. If you run a configuration for a few rides and it isn't quite right - change it. As you go note what you adjust so you can go back to your settings should an earlier method/setting work better than the ones after that. Chances are, unless you have been riding a long time and know what should feel right, you are not going to know until you get some real miles in on your changes. That, unfortunately, will take time to work through.
Proper fitment is pretty important. That is definitely your first step - which I see you have already done. That will be a good foundation, but I wouldn't expect that to be the "perfect" set up as you need to adjust things to "you".