Mist and Flood M7/M8/M9

I am having a little difficulty fully understanding the M7/M8/M9 commands

I know that

M7-Mist
M8-Flood
M9-Off

Grbl is supposedly able to control these functions. And I believe that the Currently Unavailable X-Controller has the capabilities of using these functions via the Control 1 and Control 2 outputs.

I would like to add Both M7 and M8 capabilities to my current stock electronics since I can not get my hands on a X Controller.

I assume that the A3 pin on the Arduino, controls the FLOOD command by executing a M8 command. Am I correct?

If so, how do the stock components control the M7 command? Is there a way to control M7 from the Arduino?

If i am correct on the A3 pin being controlled by the M8 command, it would be nice if someone verified my wiring before I try it out.

I want to mention that I want my Spindle controlled separately from my vac and not both triggered at the same time. I would also like to add another component to be controlled by the M7 command as well further down the road.

The reason why I want the spindle and vac separate is so that I can run them on separate circuits. I have a very large shop vac, adding up the power consumption, I come up with 21 amps just for the laminate trimmer and vac and this does not take into considerations any of the stock x carve components. Most circuits are only 15 amps, so I risk blowing breakers.

I want to control the vac with one of the solid state Relays. I understand how to wire the 110 side of the relay but the other side, I am not for certain on.

I assume that the A3 pin on the Arduino will go to one leg of the relay(3) and a GRD from the Arduino will go to the other leg on the relay (4) with the 110v power on the other side of the relay (1&2). Am I correct with this assumption?

Any help will be greatly appreciated

Thank you

Happy X-Carving!!!

I don’t know about the M8 commands but here is a bit of brainstorming if you can’t get your controller to control the shop vac and spindle separately:
You should be able to use the spindle control to drive 2 separate solid state relays, one of each device / circuit.