Taking in to account PhA and PhB-type registers, the maximum pulse per column in the datapath is at most 30mA. With 4mm by 10m lines, the drop is about 0.3V.
Let's refine: below the ALU channel, lines are 3010
m wide, so no problem. Above, there are the ALU carry prop., 5 registers, and the DBus shift register. The ALU fires out of sync with the regs, so the peak is 20mA.