Translating CS:GO 3440x1440 FoV to Overwatch

[PikaChokeMe]

I'm trying to figure out how to convert CS:GO sensitives with a 3440x1440 res and 16:9 ratio. 
Normally I've just left the calculator at it's default settings plugged in my info and took it for granted that it was giving me the correct information, but I thought I'd check and make sure. 

Is the FoV for this calculated automatically based on res? Do I have to select the Hdeg 16:9 from the dropdown for this? What about all the other FoV options? Why are they there?

Ideally I want to convert my sensitivity in CS:GO to Overwatch (103 with 21:9) so I can correctly practice on CS:GO workshop maps and apply them to Overwatch. Can someone tell me what I need to do in order to do this correctly? Also, sorry if this has been asked before. I tried to search for information on it but couldn't find any.