Hi Len!
In your first message you told that you never saw in the GUI things you read in FAQs. So I guess you do your stitchings, all this time, using the default option, the "simple interface". I use the "Specialist", but the "Advanced" can help you too with our needs, so, please, look for that in the fourth menu.
Now, when you load your photos, you can see in the first tab (photos), when display/general (right column, after the photos' information display) is selected, an "anchor" column. Now, right clicking, you can select the photo you want for the center position. You may have already read about two kinds of anchors: position and exposition. But there are other ways to position the image with, say, absolute precision! As the anchor will not move to the sides, albeit is can be rotated and even have some pitch (inclination), so you can define a precise yaw angle to fix this image center (and as result the whole panorama) to a know position, 0 degree being the center of the canvas/panorama. If you right click you anchor, or double click it, you can enter the values yourself. Just think that, after an optimization to align the photos, some values could change, but not the yaw.
And besides dragging the panorama with the mouse, in the fast preview window (with the GL in the icon) you can find a move/drag tab, with some fields available to enter angular values to apply to the shown preview. The "regular" preview window, which is slower but with a higher image quality, also has a "numerical transform" for the same purpose.
It may be a matter of personal taste, but I like to start my photos pointing to the north, so the center of my panoramas is the true north. Of course, for your planetary software, the center appears to be the East. Or South? If the pano is a 360 one, the borders will be +180 and -180, not 90 deg.
Well, I missed you used some of the preview windows already, so maybe you have discovered the numerical transformations yourself.
Be a happy Hugin user!
sincerely,
Luis Henrique