Seems to work as I had hoped
So far, PDFgear's PDF reader / writer seems to work as I had hoped. I have only opened an IRS tax form and was able to enter text ok although there is one point that I am concerned about: in the field for a social security number, on screen, the digits do not appear inside the little boxes. I will only be able to resolve this concern by printing the document to check if the numbers land in their respective boxes or are spread across the field's area.