Scott,
Good looking work.
I have a 1985 bush hog splitter which looks similar to yours. One of the improvements I think have been made on newer models I've seen at Tractor supply is the knife is mounted to the bracket on the end of the cylinder & the wood stop is mounted on the end of the Ibeam.
With my splitter, if wood gets stuck on the knife, I have to attach a chain around the wood & fasten to the cylinder to pull it off the knife. With the new models the knife retracts back inside two uprights & the wood would be pulled off the knife when cylinder is fully retracted.
Also another thing I would do if building my own today, is split the wood stop on the end of the Ibeam, so the knife would pass through the stop a little way. This would help insure the wood came apart ( when splitting something stringy or knotty).
I feel you enjoyment when building a project like this.