I wouldnt do it for the first time off a big table. I made that mistake, thought I needed to go big and throw it hard (I was trying to compensate for a few factors). Anyway, Id say go for it on a 20-25 ft table, something you can do a misty/540/backflip on COMFORTABLY. Coming up short isnt that bad with a flatspin, you just land on your side or in a hockey stop position. Have fun, its a sweet trick when you get it down smooth.
'I would be embarrassed to constantly complain about my life considering all the freedom and opportunities we have today. People that can't find anything they enjoy in life simply aren't giving it a real try.' ~Nick 311