Is the new video in one file? I am curious to know how many megabytes your latest draft contains!
i recently split it into 5 project files, because it was getting too slow (it will probably be about 10 when i am done with it). this is a step further than i did last year, last year half way through the japan project i split it into 11 different 'sequences' (which is kind of like a project file within the project file) and it helped a lot. for this one i have been using tiny tiny sequences (like 5 to 10 seconds long) but after about 9 minutes it just got too slow. so i actually split it into 5 entirely different project files. a very easy split, but i have never had to do this before, because i have never done a project this long before. the project files are not very big (maybe 20 MB each) because that size doesn't include all the images etc that are used in the video