Quad Cortex Mini Main Volume

When using the Mini as an audio interface I need to use the main volume buttons for volume out to the monitors. Problem is one press is an increments of 5 either up or down. I know I can use the screen after pressing the volume to set it more exact, but it’s very short time and not very accurate. Having monitors without a separate volume I need to have the mini volume really low, otherwise it’s very loud. I would like to have the option to have an increment of 1, or even better, the possibility to assign one of the switches rotary functions to set the volume? For example when longpressing C I have maybe 10 seconds to set the volume with the rotary knob