Don't mean to speak out of turn, but I find the thought of red velvet cake as a base for carrot cake pretty bizarre. Wouldn't gingerbread make a better base for a spice-type cake? If I were mixing this I think I'd go with gingerbread and FW yellow cake, about 60/40 for the part that makes up the cake base, maybe with just a little bit of graham cracker, so 55/40/5 (2.75% gingerbread, 2% FW Yellow Cake, and say a drop per 10ml of graham cracker or TFA Cheesecake graham cracker, plus maybe 1% of the cake batter)? I'd add some lemon to it, too, maybe 1.5%, but that's just me.