Sonya has the answer (if you don't get a reply from a local carpenter). Good for you to look for one of us, as safety concepts apply to "furniture" construction.
I'm not sure if you're good with woodwork or not, but Dungeon Delights has a kit with all the metal work already done. All you have to add is a base & 2x4's for the cross itself. The plus side is you can put the finish you want on it.