This, do not change the CSGO FOV unless you are playing solo or on a server with cheats that allow FOV changes. Also, the viewmodel FOV is NOT your FOV as a lot of people seem to confuse it with, it's just the rendering FOV of your weapon.
As for the matching method, priority one is to match the FOV. If the FOV is close (as on a 16:9 monitor with CSGO at 106.26 and OW at 103), the match method has very little impact. Other than that the big difference is that 360 distance always keep a constant 360 distance... so you can accurately turn 90 or 180 degrees regardless of FOV. The other methods (monitor distance and viewspeed) are matching sensitivity to what you see on your monitor, so they are more suited to aiming at what you actually see.
There is no best method however, it both depends on the game and your preference.