[MAK]

Vita - the center dowel is not enough - you will need supports in each tier as well -- the wooden Wilton dowels are good. If you are concerned about the wood in contact with the cake - you can drop them inside McDonald's straws [they're pretty fat] or bubble straws.

With three tiers I would just want to be sure the weight of the tiers doesn't smash the bottom tier. [Not a good look, ESPECIALLY with fondant - it gets all wrinkly and looks terrible.]

The center dowel will keep the tiers from shifting, but will not help support the weight between tiers. Also make sure your center dowel is pointy sharp and put something under the very bottom board so you don't mess up a table or counter.

Also, with the foamcore - you can get 1/4" or 3/8" thick boards which have worked fine for me....or you can glue together regular cardboard cake circles together - I would go for at least 3, putting parchment circles on top and bottom of the circles to ensure you don't get any cardboard taste transferred to the fondant.

Best of luck to you Vita with your wedding cake.