How can i use "use_stretch_projection" with nodes?

I’m doing a mobile app, as it is know many devices have different screen sizes, y use strech projection for the images to adapt, but nodes it doesn’t matches this way, i can fix it by using fixed fit projection, but sometimes depends of the screnn, just appear a black space which i don’t really like

I’m not entirely sure of which problem you have. Perhaps you can post a screenshot?

Also, have you read the manual about gui node anchors, pivots and adjust modes?