How to permanently set higher process priority in GUI

[Tony Baechler - BATS]

Hi,

OK, I'll make my question really simple.  Is there a way within the GUI to 
permanently set a particular program (in this case ffmpeg) to always run at 
the highest priority and access all available memory?  I would need point 
and click instructions for the user.  Remote access to the desktop is not an 
option, but I can send him email or a link to follow.

I personally prefer having him upload to the server, but the videos are huge 
and he is on a slow connection, so it makes more sense for him to do the 
transcoding on his end.