I produce a pdf file with this small script compiled by Miktex, however what ever font size option I choose here it is not reflectd in pdf file generated. The pdf document shows only one size irrespective of any font size option in script i.e. it does make any any difference whether I choose 12pt or 14pt or 20pt in document class.
I had the same problem, and couldnt find the solution ... there is way around but it is not that neat. Use following when you need different sized fonts