[mythtv-users] Overscan : nvidia-settings vs xorg.conf

[White Joe]

In my SD setup I have been maintaining the overscan with nvidia-settings
at 15 for the past 18 months.  Unfortunately, the settings would not
survive a reboot despite the techniques documented on this forum.  Last
night, I finally bit the bullet and began trying to find the correct
xorg.overscan setting.  It was trial and error...try a number...restart
x...rinse...repeat.  Finally I came up with the number 0.65.  

Is there a way that I could have found 0.65 more easily than what I did?
Is there a describable relationship between the value of the overscan
setting in nvidia-settings (15) and the value set in xorg.conf (0.65)?

jw