Would it be possible to support an additional pencil mark entry style which could be called Grid or Fixed.
With this style the numbers would always go into a fixed position in the box,
5 in middle, 9 bottom right etc. This would make it easier to scan for a particular pencil mark.
This can currently be achieved using Freestyle but it is too fiddly positioning the mouse finely enough - I have enough trouble getting the right cell sometimes
Obviously this would only be suitable for use with classic 9x9 puzzles but it would also be nice to allow a 4x4 pencil mark grid with 16x16 puzzles.