THE EYE
As you do more joiner photographs you will notice a common shape keeps cropping up in your big images - the EYE. There is a brief explanation in JOINER OPTICS as to why this happens. There are pluses and minuses to this. On the down side it looks awfully like an image taken with a fisheye lens. Who wants the picture they spent hours on to be mistaken for something taken with a special lens? Remind yourself that the image you are constructing is unique! No fish eye lens could produce such a picture.
This one is Upper Winchendon Church:
The bigger the image the more complicated things become technically. You have greater differences in light and tone the wider the field of vision and clearly there will be more choices and more work to make lines and forms fit together smoothly. But they can be very pleasing to the eye as well as satisfying to do.