Well, setting the size is fairly easy. Simply select the control and then set the font size from the Font menu in the toolbar. This will change the label and the text inside the control. If you just want to change the text size of the number, select the text inside the number rather than the whole control.
As for commas, there's no automatic way of doing this (at least as far as 8.2 is concerned, since that's all I have). I would suggest reading this thread.
