I'm making a 2 tier cake, 8/10 and a castle tower on the top tier. I'm going to making the tower out of RKT. I purchased 12" dowels to place inside the tower (before it has dried). I have never done this before so I'm not sure how to secure it to the cake. I plan on using bubble tea straws to support the top tier. Should the dowels for the tower go through BOTH tiers or is just the top tier enough? I am estimating the tower to be about 12" tall. My cake tiers will be 4" tall each.

If I do go through both tiers, should they go through the bubble straws that will already be there or not? I'm just afraid of making too many holes in this cake!

I don't plan on transporting with the tower on. I'm going to put it on at the party and the cake will be displayed for about an hour or so before being cut.

Thank you so much for your help!