Can someone tell me if this stupid IEM idea would work?

[holoholo]

Say I were in the mood to try a DIY rudimentary IEM mix...would this work? FM3 out 1 copied to out 2. FM3 out 1 to desk. They feed the main monitors a monitor mix of the norm...vocals, guitar, bass, keys, some drums. If I use a transformer xlr splitter or take a XLR pass through out of one of the monitors and feed that to a Behringer power play p1 and then also feed the p1 with out 2, that mean I could effectively control my guitar level and the rest of the band's levels in my IEMs?

 

[pipelineaudio]

I do something similar at our practice where we don't have access to the handy digital mixers and their personal cue apps. My mono in ear transmitter has two inputs. I send a mic that's just pointing at the rest of the band to a mixer channel, don't put that in mains, take the direct out to one input on my transmitter. My helix headphone out feeds the other input of the transmitter...this way, I can use the volume on the transmitter or the pack as master volume, and use my helix headphone knob to set the level of me vs that room mic