Thanks, but I'm not understanding the expressions entirely.
When I enter that line I get an error and the expression is disabled. [After Effects warning: Class 'Group' has no property or method name 'Tracker 1'. Expression Disabled.]
And that line doesn't make it clear to me where it adds the 100. X dimension, Y dimension? Let's say I need it to be relocated to 100 pixels to the right, and 50 to the top. Here's more or less how I've set up my Composition
LAYER | White Solid 1 | Layer with the flare.
LAYER | Null 1 | Target of the "Tracker 1"
LAYER | 00-18-15.mp4 | Original footage, tracked a point in this video ("Tracker 1")