Oops sorry I missed this notification -- it's possible, but may take a bit of work. In my system, the letters are printed individually, and each time it moves where it's going to draw a letter over by the "width of one letter". This is calculated in one place and just takes the width of a generic letter written in the font. What you may have to do instead is make something like a ds_map of the font you're using, and enter the string_width of every single letter you're going to be using. Then, in the loop that is printing all the letters, it could look up the letter in the data structure and grab its specific width to move over the y position.
So it would take a little bit of messing around, but not at all impossible - I may look into adding this feature in in the future!