I have never made a fondant wedding cake And I have some questions about how to stack it. First of all do you use a cake board under every cake? When you dowel them together through the middle how do you cover up the hole in the fondant?

yes you use a board under EACH cake......it helps make the cakes sturdier and it also aids in the service of the cake when it needs to be cut........when you dowel through the center you can just pop on a topper on top to cover the hole or what I like to do is take a number twelve piping tip and use the tip or the bottom of the tip (depending on how big your dowel is) and cut a hole in the fondant on the top cake and remove that small circle of fondant.......then put the dowel in making sure it goes down into the cake and doesn't come more than a 1/4 inch from the top.....then I put some icing in the hole on top of the dowel and then put the little circle of fondant back in place.....then take a little extra fondant and mix it with water making a sludgy consistency.....and use it to smear (like spackling) around the edges of the circle and when it dries it will match up exactlly and you'll NEVER notice it!