Upholstery and Fabrics - Channel back sofa

I need tips on how to re-create a channel back sofa once I have taken the sofa apart. I have read that I should NOT use cotton batting again but instead use foam that is cut with a serrated knife to create the tight channeling affect. What is the best way?

Hello....Iv been doing upholstery for many years....as to your question....if you dont go back to the original design and do use foam...take into consideration the weight of fabric your replaceing....if what you have is the same as you took off then it should hold its shape....the foam density is another factor...if it is to soft you will get wrinlkes in the back after setting in it a few times...I always go back to original may not be as comfy but will last....