Hi everyone, I have been wanting to do tiered cakes and I have the chance to do one for a big party which I want to push myself to do!

I am nervous as its a 4/5 tier and I have barely any experience in tiered cakes (but standard cakes and cupcakes) I have done a lot of research but I am feeling nervous about it all - baking, coating, transporting, stability  

has anyone any experience in this type of cake? 

Client has asked for 6/8/10/12 to feed 150 people  I am unsure how big each tier should be (ideally I want to keep it 4 tiers but 150 guests seems like 5 tiers would be ideal) 

When would I start baking it all before the event as I don't want the cake to dry out?

whats the best way to transport/setup and which types of dowels should I use - I really don't want any thing to collapse  

Is it a good idea to jump from normal cupcakes and cakes to a 4/5tier cake ? I do have the confidence, I just need all the tips and help I can find please!

Wow...what a challenge!

Serving wise I'd say have a look here. Not sure if you are planning on a round or square cake, party or wedding size ...

http://www.wilton.com/cake-serving-guide/cms-baking-serving-guide.html

I like to assemble tiered cakes on side as it's less hassle, but that is my personal preference. 

Naked cakes tend to get dry quicker as they are not protect by buttercream, ganache or fondant, so I'd definitely use simple syrup and make it close to time or freeze.

Support should be your biggest concern, especially since you are not familiar with tiered cakes. Some people swear on SPS, I personally use wilton plastic dowels ascend sometimes wooden dowels or bubble straws (but only to support small tiers, like your top one). 

Any tips? Plan very well, write everything down, supplies, what to organise and when to make what and how much. Time is crucial. My nerves typically kick in a day or two before the delivery day and I find it calming to follow my notes and schedule that I worked out.

Good luck and let us know how it went...

When you say a naked cake do you mean one without any frosting/coating of any kind or a very light coating (what is call a crumb coat or dirty iced)?   As Julia mentioned completely naked cakes do dry out very, very fast.  Those with crumb coating of some kind hold up far better. 

As for servings, I always count servings of a tiered cake as wedding servings for pricing.  If the client wants to serve larger servings they have should order a bigger cake.  6x3" R is suppose to serve 12; an 8x4R=25; 10x4R=49 and a 12x4=54 (not sure on the 12").  However, it is a tower - very, very unstable for delivering.  Since you are not icing/decorating this cake I suggest stacking the two bottom tiers and boxing the others to stack on site.  A much safer choice - especially if the delivery route is difficult :)