Anyone tile over tile in a shower? Tips or regrets?

[Marian Smith]

I am considering tiling over tile in a walk in shower.  There is enough play in the Delta valve handle to accommodate another layer of tile and I have found drain extensions at HD.  Custom building products has a primer specifically for this purpose...but I was going to set the shower pan area with epoxy.  Anyone done this...and any regrets? Thanks.

PS. It is not a standard size or I would put In a cast iron pan.