Sigma 8mm Fisheye Canon 350D MrotatorCP

Setup

With the above combination I can shoot a panorama in either six or three shots with yaws of 60 or 120 degrees respectively.
For the three shots process, position the camera 4mm backward in relation to its calibrated position for the six shots process.
If your aim is the three shots process (a time winner for cheap real-estate service), you will be better served with a Nikon D70 for which the MrotatorC was originally designed. It has a larger sensor, which gives you more overlap. The overlap of the images with the Canon 350D is extremely small.

The process that works for me (with PTgui):

import source images
set approximate lens settings
set panorama settings
the crop is automatically good
set image parameters
- distribute images by yaw (thank you Joost for the Fill yaw function!)
- roll all images -60 (the Agnos MrotatorC holds the camera at 60 degrees to use as much possible of the sensor surface)
- set approximate pitch (thank you Luca for the great idea of orienting the camera slightly up, giving better coverage of the zenith)
set control points (i add at least two vertical lines)
first advanced optimizer run: optimize for pitch only on all images, including anchor image, linked (the camera is slightly tilted upwards on the MrotatorC and the angle can not be precisely measured)
second optimizer run: if necessary, optimize a second time for all parameters
blend and stitch, serve hot with either a Java applet or QuickTime

Can be stored in PTgui's lens database

the above process works with my guinea pig, a little 5x5 (1.50mx1.50m) shower/wc room, as well as with some larger rooms.
Hypothesis: since the entry point of the lens changes with the angle, for a perfect, uncorrected stitch exact slices should be used, like an orange. To be verified.