Thanks dwarren2,
It finally dawned on me to adjust the TV with the guide displayed, and then to use the Receiver's asterisk button, to flip through the various formats. I was trying to do it in reverse, fit the picture to the screen, having the guide flow off of it.
What I didn't realize was that the asterisk button only effects the picture and not the guide, so that once the the guide is set properly, it always remains the proper size, then allowing a quick resize of the picture, using the asterisk button, to fit the broadcast. I found that for most, the "zoom" works well, but that on a standard broadcast (4:3) the top and bottom expands beyond the screen. Then a quick run through the asterisk formats to "normal", fixes that, bringing in the sides showing a black border on each side. HD broadcasts seem to fit the screen perfectly in "Zoom" mode. Thanks,