Hi Antony; just use the clone tool as you normally do. Then add a solid layer and cut and paste the Paint effect from the original layer to the new solid. Then activate the paint on transparent check. Now you can add a levels or any other effect.
Hi, you can change the corner radius of a mask while creating it by click in the up and down arrows of the keyboard. One you release the mouse botton tou can’t change it anymore… If you need to change it later, you should do it like Joe said.
You can use different images at different resolutions so you don’t loose quality and that way it’s easier to handdle the ae file instead of a single huge image.