I have been using the 301 or 301-1 for about 20 years. I was never able to solve my tendency to curve my cut at the end or the beginning of the cut. I now still use the Logan base with the hold down bar but I use a Dexter with it instead of the Logan cutter and blade. Now I get straight cuts.
This is easy to overcome if you press the knifeholder sideways against the ruler while you cut. I had this problem only with the first two cuts. Then never again.