I develop my 8x10 negatives in home made ABS tubes. I don't use "full" volume of chemicals, but rather I roll my tubes by hand slowly and alternately in both directions to make sure that the negatives are always wet with chemical. Because the chemical doesn't always cover all of the negative, I can't let them stand, so constant agitation is what I have to do. I have read somewhere that if I roll the tube too quickly and always in one direction, I will get something called bromide drag? I think I understand that to be (in very simple terms) a mechanical displacement of part of the emulsion causing a change in emulsion eveness and density. So, if this is correct, the question is : If the rotation speed is very slow, say just fast enough to keep the chemical constantly fresh, but the direction of rotation does not change, might I still suffer drag? or, is the directional change absolutely necessary?