Zeroscope 1U accurate enough for calibration?


If I want to calibrate my hermod sequencer I need to measure its output voltage (from -4v to +4v in 1v increments I think). I know the Zeroscope 1U does not measure voltages directly, but could I use the grid in this scope to measure/calibrate voltages with decent accuracy?

I read in the manual that one can change the voltages per grid division, but not sure how finely we can do that, but I think if I had it set from -8 to +8 volts, and I aligned the incoming voltages with the grid, I could tune hermod, right?

Anyone that has the Zeroscope could maybe try this please?

Thanks in advance.