UPDATES: my video card died last week, and just today I replaced it, with a more powerful and faster one, so I'm back to this project!
I want to say a big THANK YOU to nirbateman, who kindly offered his help checking the whole movie and spotting the shots with artifacts; without his help, this project will still be a lot behind its schedule!
Right now I'm processing the pre-final video; only few shots/scenes should be fixed after that, and the most time-consuming process will be to find out (again) the wrong ones, then choose the best method to fix them. Probably it will take few days this time - I strongly hope so...