Not sure I have any pics of my fish room, but for water changes here is what I did...
It is all based off of a 55g tank, but the vessle you use is up to you.
The 55g has one drain bulkhead on it and a standpipe. This drain then splits right away with one line going to the sump and another line going to the house drain line. Each has a ball valve on it. I also have a split off of my return pump going to the 55g water change tank.
My water change process couldn't be easier. Starting with an empty tank I....
1) Close the line going to the sump and open the line going to the house drain line (I keep the drain open in case I forget to turn off my RODI and I overfill the holding tank)
2) Turn on my RODI unit and fill the water change tank
3) Add salt and mix
4) Close the line to the drain and open the line to the sump
5) Open the line off my return pipe and let the water circulate for a day or so
6) Close off the return pump line (now the tank is filled with mostly "dirty" water) and the drain to the sump
7) Open the valve to the house drain line and unscrew the stand pipe, thus emptying the entire tank.... and I'm back to the start.
Pros: You don't have to measure anything and the water change actually happens somwhat gradually since water from the return line in my sump is just displacing "new" water in the holding tank and the holding tank water only drains at the rate that you are pumping 'dirty" water in from the sump.
Cons: SOME of the water I end up with in the changing tank is "new" water... My system, accounting for actual water volume (not rocks and sand) is 125g display, 60g Fuge, 30g sump and 47g water change. That is 260(ish) total volume. So when I mix it all togehter the water change tank is 18% of my total volume, thus I'm "wasting" about 8.4g of new water.
Hmm... Thinking aobut it more, if I keep the water change tank on-line longer then really nothing is wasted. I'm just closing off 47g of the main system, draining it all and then replacing it with new water.