How far in advance can you make a frozen bc transfer? Not sure how long it will last in the freezer.

Pretty much forever. One of the advantages of an FBCT is that you can make it in advance. Then the day before delivery, just ice your cake, plop the FBCT on it and add a border. TADA - instant cake.

One of my main problems is making sure that it stays safe in my disaster of a freezer. If it's going to be there awhile, once it's frozen put it in a ziploc or something so it doesn't pick up that freezer smell!

ditto to marccrand's response.

I find the longer it stays in the freezer the easier it is to transfer.

I also have a question about a FBT. I have tried making them and have succeeded when placing them on top of a cake but twice have tried putting them on the sides of a cake but when they come to room temperature they fall of the sides of the cake. I have tried putting fresh buttercream behind them to see if they stick better but have had no luck in keeping them on the sides. Do you know if I'm doing something wrong?

Thanks so much for the info guys. I have not tried to make one yet, hope I can do it okay.