To a first approximation, assume the two wires of the each pair are near, and the out and return pairs are far apart. In the limit, when near/far = 0, each junction in the group of 4 crossings has the same voltage, and each wire will carry 170A.
To see what's going to happen when the spacings are significant, the resistance of the wire, and the current flowing through it, creates a voltage drop on the spacing between the two wires in each pair, proportional to their spacing and resistivity. This means that a higher current flows in the 'inner' wire of each pair. The wider the intra-pair spacing compared to the inter-pair spacing, the larger the imbalance.
It's worth pointing out that in a real experiment, the contact resistances may well be more significant then the resistance of the wire. These would tend to dominate the wire length resistance, and tend to equalise the currents. They would also be very pressure dependant, and make an experiment unstable and difficult to measure.
It's quite easy to solve for the exact currents, once resistances, including contact resistances, have been specified. We also need to specify what's driving the 170A, whether it's a current source, or a voltage source and some source/load resistance.