Well, my workflow is to set up the timeline to my desired output and then only scale the Video output.
I am using an older but still lovable JVC broadcast monitor to check my colors.
Its PAL only, but still blows anything LCD out of the water.
I work mostly in 1920 and deliver in 1280.
So my Timeline is set to 1920, the render output is set only when I am ready to do so and the video output is set to PAL.
By the way, this also dramatically reduces the lag the Decklink cards adds.
A slice of color...
DaVinci 8.2.1 OSX 10.7.2
MacPro 5.1 2x2,4 24GB
RAID0 8TB
GTX 470 / Quadro 4000
Extreme 3D+
ICA Instructor
http://www.icolorist.com/Sascha.html