Let me think about this. I have a DRY helper method below these two methods that take all the params but I just did not want to have to remember the correct format string and time zone name where ever these are used but maybe that's a little bit of overkill on my part.

One other question: what do you think about adding in the timezone offset or maybe tz abbreviation at the end of the file name? Would either be worth doing in your view?