I have added some upgrades replaced all 3 vessels, and made a keggle mash tun with amnifold. I made the manifold for my bottom drain kettle so it would screw into place. It sits about 3/4" away from the bottom on the outer edges and a couple inches high in the middle.
To reduce dead space I actually drilled 1/8" holes in the base of the copper manifold fitting that screws into my stainless mash tun fitting. I think this allows the highest gravity wort resting on the very bottom to slowly drain out without providing enough flow to allow channeling.
The center fitting I had to make by drilling a hole through the side of a T fitting and sliding a piece of copper pipe with a hole drilled through so the copper pipe hole was facing down. Then I had to solder it in place. You'll have to forgive my poor soldering, I am definately not a plumber.
With manifold installed.
I currently fly sparge and I made this sparge arm so I could use different lengths of slilicone tubing to adjust height depending on my mash volume.
This is my current setup, I recently replicated the process by building a 1 gallon brewery for test batches (without the pumps).
This spring when it warms up, I plan to add legs to the other 2 keggles and get rid of my improvised wooden brewstand.