The reason people say 90g is for the rock. it IS recommended to have over 80lbs of established rock to have a healthy pod colony without supplementing any.
I believe if done right a pod tank can work. IF. i have no idea if I'm doing it right but I think I am. This isnt toally off topic so heres a pic of my pod tank. I added another 15lbs or so of LR
today, just got back from lfs
It will take alot of work if he isn't eating prepared, but there are success stories out there. But there are also more tragic outcomes too. We just don't want you to have to watch your fish die is all.
Do you have any pictures of him yet? I'd love to see em'