STOUR is a propretiary software from JPL which searches "in a grid" for good fly-by sequences.
Roughly works like this: it grids the planet positions. It computes all Lambert arcs between the gridded positions during a tree search. It returns good "close to ballistic" trajectories, candidates to be transformed into low-thrust.
You will see there that, for single revs the pork chops landscape does not change much using expsin w.r.t. Lambert arcs. After we have a good code in place, I would like to reobtain that result as a first check.
I found this in the report, is this usable for finding Nmax ? >a particular heuristic has been implemented: for a given transfer the number of allowable revolutions can not be larger than the ratio between the transfer time and the shortest revolution period between the departure celestial body and the target celestial body