Interesting machine. I'd be worried about that method of agitation though. The builder really needs to analyze the resulting negatives for development uniformity.
In his meticulous testing, Richard Henry constructed an automatic agitation machine, although it was only for agitation and did not automatically pump chemistry in/out. In testing for uniformity and agitation patterns with inversion agitation, he found that not only were complete inversions required, but that when inversions are machine controlled some rotation about the tank axis was required in order to "randomize" the agitation.