well first i should probably describe the tank. it's a cubical shaped tank, and takes 1.5 liters of liquid approximately. there's a holder inside for up to 12 sheets of film. the film slides in from the top, and the ridges are curved so as to curve the film. the ridges that hold the film in place are about 3/8" high. so the film's rebate area has 3/8" on either side that has impeded flow of some sort. the gaps are pretty wide, perhaps 1/8".
the tank is not invertible. therefore i agitate by grabbing alternate corners and pulling up and down, to slosh the developer around. i make sure to alternate pairs of corners each agitation period. and every once in awhile i'll pick the tank up and swirl it around instead, again at an appropriate agitation period.
which is 5 seconds for every 30 seconds of development.
rinse, fix, wash.