Seen people with similar set ups. It's important to not have sharp substrates. H
However people told me crushed coral was a poor substrate, but I had 7 different rays on the that substrate with no problems whatsoever, in fact they seemed to enjoy it because after I took my Pearl stingray off its started to act weird.
I have a 150 right now and making room for a big tank soon. Just waiting for something to pop up on craigslist lol
Im not sure what I'm interested in.. I'm not trying to spend a fortune on one.. So I'm guessing probably a motoro