I have always used toroidal agitation for my small tanks. I have the Paterson system and that seems to work just fine. I have recently started to use the old school metal tanks. I like them for dev. economy and ease of controlling temperature. However, the film on the inner part of the roll does not receive the same amount of agitation as the film on the outermost part of the spiral. That is --- the last frames of the roll. I posted this problem on the Film Photography Podcast forum on Flickr, but I would like to hear more weigh in on whether I should just give up the metal tanks all together. I have heard that it is best just to invert the tank with out the twist. This makes sense as it would seem that agitation would be more even as long as the axis of inversion is varied. What are your experiences and/or impressions?