Thats a lot of film to be trying to shoe-horn into a Jobo tank, even the largest, without some serious tricks.
You could try going back to the dawn of cinema and making your own racks; vertical or horizontal but both have their drawbacks.
The varying density you see in silent movies is almost invariably the result of sloppy vertical rack processing of the release print and even sometimes the original negative; NOT variations of hand-cranking speed as everone assumes.
Unless you're willing to put forth a lot of effort and risk failure, I'd stick to a commercial lab and their continuous processing machines OR get a LOMO tank for b&w.
My 2 cents...