When the brightness is set at the maximum level, max current is 25mA.
But I am not sure it will work with relays because the displays are multiplexed, which means that only 6 displays are switched on at a given time and the other displays are OFF.
displays are switched on and off very quickly so that the eyes don't see that.
So if you connect a relay I think it will switch on and off very quickly.
The Pro-Shift instead is not multiplexed so it should work with relays.