We were talking about groom's cakes in another post, and I decided to post this question in a separate post so it will be noticed

I am thinking about doing a fun groom's cake but I am not sure if I should present it at the rehearsal dinner, or at the actual reception. The benefit of presenting it at the reception is the fact that all of our guests will have a chance to see it, and make a big fuss over how cool it is! However, I don't want to have a huge groom's cake (to keep the cost down) and I'm having about 200 guests at my wedding. My question is...when you have a groom's cake at your reception, is it expected that every guest gets a piece of the "regular cake" and then also a piece of the groom's cake? I don't want to bring out a groom's cake if it is too small to feed every guest...so maybe I should do it at the rehearsal dinner? Thoughts?