Updated: Apr 3, 2018
Was able to get a couple things done this morning before having to go to my shoot.
Drilled out the 8 drain holes from a 7/8" hole to a 1" hole so the EK compression fittings would fit through. These will be attached to the 8 EK Ball Valves that will drain the different parts of the system. Since the desk can't be moved/flipped it will be easier this way. There will be 4 more valves plumbed into the system and run to these locations. Basically all the low points of the loop will have a drain. It's probably a bit overkill but I think it will work well.
I got the two drain valve lockouts drilled. I drilled 2x 1/4" holes across the top of where the valves will go. This will allow me to slide a 1/4" rod which will hinder the opening of the valves. I will also drill 2 small holes in each rod to put small pins to lock the rod in-place.
I also drilled the holes to secure the wood desktop to the frame.
I welded the feet to the bottom of the desk. This will keep it from sitting directly on the floor. I also started practicing my copper pipe soldering. I'll be starting that tomorrow. It's getting close!