I know the ideal way of using two-bath development is to have A in one tank and B in the other, and to move the film from the first to the second. That requires a darkroom; would be hard to do in a changing bag. For those with experience with Diafine: are there any issue that crop up in using one tank, and pouring the solutions in and out? It seems to me that would inevitably increase carryover of A into B, as most tanks always seem to keep a little solution even after you think you've poured it all out. But that reportedly isn't an issue, except that you'd eventually reduce the amount of A you'd have on hand.