Partial video blurring using nodes only Youtube video I am loosely following: Face Blur with Motion Tracking

How can I use nodes (except render layer node) to blur part of a video that uses tracked markers from movie clip editor?

I want to do this so I do not need to render the same circular mask for each frame. It is taking up a lot of time even with Cycles engine at 1 sample. By using the nodes, I hope to speed up the process.

My node set up so far (blur position is almost right, but is offset a little from marker position):
Problem is scale moves image to center but want scale to move to origin (bottom left).

Solution is scale to desired size then scale to render size and move to origin.