Hi there Oldgraymare,
I recently purchased something called Clearly Perfect Angles. It is an acrylic template to place on your sewing surface under the needle to make perfect angles. Well, it didn't work out so well for me, so I cut it up into pieces and really made a mess of it. OKAY: here is the point of all this. I have pieces of this I will mail to you at no cost. It should work perfectly for what you want. Place it in the area where the rough spots are and make a needle hole and you should be good to go. Please PM me with your address if you are interested.