YG7tJsK18FuNhr: Run Peixoto.bat, click Add Game, select OpenGl, click the blue text 'Game Path', navigate to SoF.exe and select, type SoF as entry name, type sof as path, leave arguments empty (set arguments manually by edit sof.ini file in peixoto/profiles/sof.ini file if you need custom args, with args=+set yourargehre line), hit Create.

Now you have a SoF entry in list which can be used to launch.

Go to that menu entry, ensure forced resolution = Enabled.

Now if you want 16:9 ratio but smaller resolution scaled to fullscreen, you take half your monitor resolution to have 2x increase in HUD Size.
Mine = 1920x1080
So I use = 960x540

2 ways to achieve this, either:
1. Drag Limit resolutions slider in the above until it says 960x540.
2. With sofplus in-game use the command "set _sp_cl_vid_mode_0 960x540"

Hit 'Play'

ensure inside SoF console (escape key twice, or ` ~ ingame) :
vid_fullscreen 1
vid_restart

Enjoy.