How to increase the size of the caracters in the Orbéon PDF generated ?

Hello, We have developed some forms which can be printed, but the font used for the field is too small to visually impaired people. We have Orbeon 3.9.1 PE Actually, we have to generate specific extend pdf with Adobe X PRO, but it's very long to rename each field of the PDF (a few hours for a big form). How to increase the size of the characters in the forms generated by Orbeon PDF ? Thank's Patrick Daburon Conseil général de Loir-et-Cher France