OK so an update to what I've found, using nssm I am able to run Awesome Miner as a service, however the option to run interactively is only supported on the local system account. You need it to run interactively to access the GUI. When I ran it this way AM had no miners set up and it was like a fresh install.
In theory this would work as a service if I wanted to register AM and set up all my miners again under the local account, and every time you ran Awesome Miner it would have to be ran as the local user.
Unfortunately all the AM settings are saved on my user account, not the system account.
As a workaround I think I will do the Windows auto logon thing that you mentioned and put a .bat job in my startup folder that will immediately lock the screen after signon. That is not the best solution but It looks like it might be the easiest.
Native AM support as a Windows service would be great though, I'm not sure why it isn't an option already.
I just use a smart plug with energy monitor to give me the actual wattage use of the entire mining rig.