What width strips were you trying for?
What is the narrowest width of the strips you cut?
If it's only "a little bit" too narrow, one can compensate a little bit by using a narrower seam allowance.
Perhaps I make more work for myself, but I do not cut a zillion layers at one time. Why? Because if I botch something, it's only one or two layers instead of eight to ten.
Maybe show use the fabric you were using?