I would hope these 450 tons were euro's for you ;-)
There is no law that forbids you to use photoshop in post of course, certainly as it is as easy as the clip showed us.
I agree that there are sometimes projects where you need to do some work using transparency. Your project is another example of the fact that moving objects make things a lot more difficult, certainly if they do not fit into the frame of one photo.
The clip also showed that for each pixel in the final panorama you would like to have a source photo without the moving object at that pixels or to have any moving object fully inside one photo. That way you can allways remove objects that are only partially in view.
When moving objects are too large to fit into a photo, then you have a more complicated situation. Using multiple focal lenghts is a possibility. Shoot higher lengths before the action starts and fisheye when your objects are moving.
Hans - what i can tell you:
I needed to place my tripod/head/camera to a certain position i choosed before. Then i had to leave the area for security reasons: nobody was allowed to stay there aside from the crew that controlled it all. The cranes are radio-controlled - so during the preparation-period i needed to find out which radio-frequencies i can use for startingt my head remotely (about 50m distance, surrounded by big and heavy steel constructions). I was lucky for being able to use my american radio device which works with an "uncritical" freq. - i would NOT have been allowed to use WLan for starting or even controlling the head.
I could not approach the camera the whole time for changing anything at all. The movement of the cranes - and so of the object - sometimes was clearly recognizable and sometimes was hardly recognizable. Nevertheless there were several positions which were interesting for a shoot.
The head/camera took about 40sec. for a full sphere in this situation (5D2, 15mm Fisheye, Panoneed, 6 shots @25% overlap). The moving of the objects was minimal during this time - and THAT made things more complicated. More movement would have made it easier because of clearer spatial differences. Low movement takes you x times the effort for editing because the several states of movements are not clearly seperated from each other but overlap massively.
In this i case you only can edit them VERY precisely by painting with small tools and heavily enlarged viewing the details you´re working on.
Doing that in Photoshop would mean to edit without getting a feedback from the stitcher´s editor. So - that´s no way.
Masking in PTGui was the perfect way doing it precisely. In the resulting stitches you can search at 100% - you will find not a single blurred or ghosted area . .
Took it´s time of course - but it´s definitely worth the effort.
Besides: it was absolutely impossible to shoot a Nadir - the fact the tripod stood on a metal grid platform and looking down @-90° showed what was
below the platform didn´t make it easier . .
I needed to retouch the Nadir without being able to make a shot of the grid alone without the tripod-legs. Pure retouching job. Not knowing this it´s hardly recognizable.
Besides: nobody cares for a perfect or not Nadir in such a shot of an impressing setting up such a machine . . .