I'm almost done with a 3 tier dummy take for a wedding. What a week!

There are 2 x fondant figurines on the top of the cake. As it will be a little top-heavy with these, is there any need to dowel the tiers for support, or will a whole lot of royal icing that I'll use to glue the tiers together be enough support? Any other structural issues to be aware of for dummy cakes? Thanks.

You don't need to dowel styrofoam tiers. I can stand on one of those and it might press down a little (I just tested it with a 5" dummy and yep, that's what happened) but a topper isn't going to do anything to it.

As far as being top-heavy, as long as it's on a board to carry it around it should be okay. I put a skewer through the center of my dummy cakes to hold them all together but that isn't for support, it's just to keep them from skooching around.

As costumueczar mentioned there is no need to dowel dummy tiers.  If  you used royal to anchor them together you probably don't need the center dowel either.  It would not hurt to use it if you make sure it goes all the way down into the base board  you are using.  That board should be no less than 3-4" larger then the bottom tier ie: 16" dummy on a 19 or 20" base board.   

I skewer the styro tiers together also.  Not for support, but to just keep everything lined up.  My fondant figures would have had a skewer built into them also.  And if I forgot, I'd just RI them to the top tier.

Thanks for the advice.

I ended up just using a whole lot of royal icing between the tiers. Lifted the whole cake by the top tier this morning as a test and rock solid, phew! 

I've skewered my figurines into the top tier, so they shouldn't go anywhere. Bit nervous for this cake, it's travelling for 5 hours to get to the wedding venue. The only thing I'm worried about now is one of each of the bride and grooms hands - they are holding hands. All is solid, but hoping any bumps in the road aren't enough to crack anything.

Cross your fingers for me! :)

Ditto the above, I've never needed to dowel a dummy, they are strong enough to support each other. But then I've never done anything more than five tiers... :)