I like to use precuts but they are irregular some of the time. To combat this problem, I sew two strips together
with the larger one--sometimes the exact size-- -on the bottom.The smaller one is laid on top so that I can see the
lower and the upper strip is NOT over as far as the needle. I get much closer to the correct size finished that way.
I have not tried to use to cut them other than to piece strips and use those to cut into patches. Brenda Henning's
later Strip Therapy books talk about problems with undersized strips and what I do came from reading those.
There are places that have strips that ARE correctly cut without the pinked edges and they are much better !