Excel Comments

I have been trying to work out a way to increase the font size of the comment boxes in excel via macro.

I am able to get it to work on the workbook open but this is slowing the opening of the sheet as there are many comments on the sheet and it takes a while to process through all the comments. What i would like to be able to do is run the macro on each comment as it is entered or saved so that when it is next displayed it is in the bigger font size. 

If any one can help Thank you in advance.