Forgive my obtuseness but when I use the Rotate/Zoom tool it does change the size but it also moves the layer's position in my image. If I follow your second suggestion, it gives me a new image which is blank. That is, it is the same size as my layer but just has a white background.
Because of the the application this is used for I need a precise location of the layers on the image (within a single pixel) and the same for the size of the layer. I have all that now but I see no good way to edit either the size of the layer nor its' location.
Thanks for the help