Corner pin resize transform tool

Hi guys,

Am doing some corner pinning and cant remember something that came in real handy....

What is the cheat to make the transform tool in the corner pin node rescale to the size of the image?

At teh moment I am trying to skew in a multiplane but because the image is so rescaled it is tiny and the corner pin tool is massive in comparison making it hard to be accurate.

Am sure i used a tip once where you put in two corner pins and do some kind of invert or something to make it work real nice...

Anyone know this tip?