You might try approaching the problem from a different direction, and use Keyboard Maestro's built-in Copy action:
The advantage of doing it this way is that the macro won't proceed until the copy is done, as explained by Peter in another thread:
If you absolutely can't do it that way, then you'll need to use a Pause Until after your Command-V and check the file size repeatedly in Terminal until it's not changing. You can see an example of how I did that in my AppWatcher set of macros (specifically, it's in AppWatchAdd):
This works by repeatedly measuring the size of the file being copied and stopping when the size stops changing. Obviously it would have to be customized for your needs, but this worked for me (when I needed to know if an application was done installing).
-rob.