Is there a way to specify a default font size, and still have a multi-line form where the text will shrink as more text is added?

For example, I would prefer that the default font size of each text field on the form is 9 pt. with the text resizing as necessary once the field is filled to capacity at 9 pt. I don't seem to be able to specify that as a default and also use the multi-line, resize settings. It seems to be either 9 pt. font, or Adobe's default font size and the ability to resize as text is added.

Thank you.