Lachlan: with the drum it stands upright and the developer get pour in to the top which then flows down the tube into the bottom of the drum making no contact with the film until its turn on it side when put onto the drive magnet. At that point the developer flow 90 degree to the marks for a short time before the drum starts to rotate in the same direction of the marks. I don't prewash.
James: the tank is a 2800 series jobo but the print drum cup has been replaced with a funnel and centre tube which I think turns it into a 2500 series. I don't know if the inner make-up of the drums are different, I don't think so. Mine has ridges about 2mm and spaced about 20 mm apart, then there are 4 bigger ridges which fit 8 inch wide film, or using the other ridges fit 7 inch. On to the ridge you can fit a small split tube which traps the film in place but it seems to stay in place without them as well.. In short I'm using it like a paper developer tank. I didn't know you could get a 810 spiral like the 45 one.