When do qgraphicsanchor layout positions change the positions of items

I am trying to use a qgraphicsanchor layout to control item positions within a view and am experiencing issues with knowing when the layout changes the position of the items. I am able to see the positions if I set the relations and then set the layout, but after this I would like to change the layout relations/item positions. eventually the layout changes do take effect, but this is after when I would like to use the position of the item. Is anyone able to give suggestions on different ways to see this, or if I should try something else?
Thanks