We have a chain tool that looks just like that Gee Two linked to. I think we bought from the same place some years ago based on CD recommendation. Works great. The guides line up the chain and help to hold it in place. Assembling/breaking chain takes a bit of technique. Easily learned through practice.
We have also found this
tool useful for putting master links on chains.
For those considering poly cord for drive train, keep in mind that one wheel per side on Inflight's nicely done robot was direct driven from the gear box which plays into how much torque needs to get transmitted to the other wheels by the poly cord. The pulleys for the poly cord where also large which helps with the force transfer.