I'm working hard on the second edition of my Photography For Real Estate e-book. I'm adding several new chapters and updating several of the existing ones. One new chapter will be on the process of shooting 360 images for real estate. (Everyone that has purchased the first edition will get a free copy of the second edition).
Ever since I started using my 1Ds for 360s I've been shooting them with the camera body horizontal. This is possible since the image circle of my Sigma 8mm fisheye fits entirely on the full frame sensor so it doesn't make any difference if the 360 frames are shot in landscape or portrait mode. They are effectively the same.
Shooting with the body horizontal makes is possible to rotate the camera an lens around the no-parallax point of the lens very simply. It's so simple I just use a short section of earthquake strapping (for those that don't live in earthquake country any metal bar will work). You just cut and drill the metal bar so that the camera and lens rotate around the no-parallax point of the lens. You attach a Bowens Quick-release plate assembly to each end of the strap to make attachment of the camera and tripod easy.
If you'd rather not build your own 360 shooting rotator you can purchase a precision version of this strap and rotator at reallyrightstuff.com. The cost for the ball head, the quick release mount, and the pano elements package is $790 for my camera. The reallyrightstuff.com package is a precision, adjustable bar that allows you to easily adjust the camera forward or backward to get the position perfect.
While writing this chapter I realized that those 360 shooters that use the Sigma 4.5mm fisheye designed for APS-C sized sensors can use this money saving technique too.
I need to point out that by using the Sigma 8mm on a full-frame body or using the Sigma 4.5mm on a APS-C body you are not using as much of the sensor as you do by using the Sigma 8mm on a APS-C body. I've been happy with the results that I get with the Sigma 8mm on my full-frame body.