My slots use:
- Left Alt
- Right Alt
- Left Ctrl
- Right Ctrl
- Left Ctrl + Left Alt

My spread out key is Shift ~.
Most of my hotkeys for mapped keys, are either keys of Shift + Key.

Maybe not using the same modifier as a slot FTL modifier for movement is important.
I do have a few Alt + Number mapped keys, and FTL Assist works just fine with those.

It's a little hard for me to troubleshoot the default formations in IS Boxer...
I made mine, at a point when formations did not exist, except for custom formations done by individuals.
So I can explain what I did, but am not sure if its the same as the default formations from the wizard.