How do I set a default font size for text boxes in Markup on iPhone?

I use Markup using my iPhone to add text boxes to pdf document to fill in fields, and even after I set the font size on a text box in a document, every time I create another text box it reverts back to the default font size and it drives me crazy.

Please tell me there's a way to set a default font in preview. It's such a basic function and yet, I don't see anything that allows me to do it. Any help would be appreciated, thanks!

[Re-Titled by Moderator]