Welcome, I am new to this site and I just created my profile. As for your question. I usually measure my top in 2-3 places across and up and down because of the way material stretches it may be different in areas. Next I take the largest measurement and I cut my backing to 2-3 inches larger than the top. I lay it out and tape it down with painters tape, then lay my batting then the top. I'm not sure if that answers your question or not. I'm sure there are a lot more experianced quilters out there tha would know better but this works for me. Hope to see you on here again and have a great time quilting.