I had several large trees moved a few years ago. 2nd the individual valves and water. The water is simply a lubricant so the blades will slide and not stick to the dirt. The water isn't there long enough to soak in and help. Seeing a larger conventional KW frame twist and turn as the blades went in (and tree came out) was impressive!. The smaller skid steer model wasn't bad, but nothing by comparison.
I would look at having a 55 gallon counterweight (sprayer) rig for the water. All pumps and attachments are worked out for you already. You could probably come up with a simple bar or rod to run all the blades at once if you had individual cylinder controls.
I believe both units had a swing open gate/blade on the far end to get around the tree. You will need to make sure your loader and front tires can handle the load. It might even make some sense to explore a 3 point mount design for a conventional tractor. Just a thought, as you are starting from scratch. Plus, you can see your positioning easily.