I would recommend that you do not do too much in one sitting. With the SID method, you have to handle the bulk of the quilt all the time and there are two problems I found:
1. I get incredibly tense muscles in my neck from holding the quilt up and focusing on the ditch.
2. As I get tired, it is harder to keep the needle aligned in the ditch.
I sew a seam or two, then I take a little break. Makes a big difference.