One trick that might help. I bought the cheap 3 buck, two wire, digital voltmeters. I put the same plug on it as the charger, and put it to measure the voltage between the charger and the battery.
This way, not only can I tell which setting it's on by the chargers output voltage, I can tell if I have a full charge at the end. Good to know before you set out, YES it really did charge fully.
Chargers really should have a volts display on them!!! Its a 3 buck item, retail and shipped! So don't tell me it costs too much to do.