I do not currently have the means or space to build something like this, but I was on a lot of mescaline in a isolation tank once. It was the most moving experience I have ever had.
I used to try meditation a lot, but it never worked particularly well because of all of the physical distractions. I have now come to realize that sensory deprivation areas are the ultimate form of meditation. They truly allow us to dive deep into our minds in ways that don't seem possible to average people.
I do not want to "put down" normal people who practice meditation in their bedroom or wherever. It is better than not doing it at all. People have done it for thousands of years with much success. But the isolation tanks/sensory deprivation rooms are really the key for diving deep. One day I plan to purchase a really good iso tank or build one for myself.
With the room that you're building, won't you still be able to feel the foam/padding? In the tank you are suspended in the body temperature water so you really don't feel anything, but that salt water requires a much bigger investment of money and time.
"Think for yourself and question authority." - Leary
"To step out of ideology - it hurts. It's a painful experience. You must force yourself to do it." - Žižek