Again, I don’t actually have a Maslow at this point so I’m just speculating. I also haven’t spent any time playing around with the Arduino so I don’t know its limitations. If the Arduino can’t handle the added circuitry, that obviously kills it. Beyond that, getting wires to the Arduino from the sled should be pretty basic.
A less accurate way of compensating for the tension in the chains would be to use the equations from @pillageTHENburn 's post to calculate the static tension in each chain in real time. It doesn’t account for the friction between the sled and the workpiece (waxing the bottom of the sled could help) or the resistance from the bit cutting the workpiece, but its a step in the right direction.