Hello I am doing a 4 tiered dummy cake but i was wondering if it is ok for the
1. Top tier 6in cake to be real,? .Will it hold fine on the other bottom tiers 8in.10in, 12in?

2. Do i need to use dowels for any tiers? What about for real and cake. Please help! This way is much easier and cheaper for me to do for friends wedding cake!

1. Yes, and yes. (you can skewer it to the 8" if you'd like, but it isn't necessary.)
2. No, not required for styrofoam dummies. (a smear of BC or RI is enough for all tiers.)