Hi I've got a 12" round rainbow cake which will be around 8" deep which is the best way to cover it with sugarpaste wrap round method or one whole piece it will be ganached first any advice would be appreciated jay xxx

Hi jay, when I started making double barrel/ tall cakes, I read somewhere, if it is over 8 inches tall - wrap it, if under 8 inches tall -cover with a whole piece.   So that is how I do it. 

Years ago, I remember rolling out fondant on a large sturdy cake drum that was dusted lightly with powdered sugar and slowly letting it drop off the edge as I moved over the cake.   Or a mat can be used.  That much fondant is heavy.   

 Now I just use a large PVC plastic pipe to pick it up and drape over the cake.  Chill the cake real well, and work quickly.  

I hope this helps.  

I'd suggest looking up youtube videos or online tutorials for barrel cakes or tall cakes.  I've seen them but haven't yet tried a tall cake.   Good luck!