That’s interesting because I’ve found the Explorer’s FOV listed as 105-110°, but reviews said it felt more constricted than the Rift or the Vive which also have 110°. 
According to risa small FOV is arround 120° so it should at least not be much bigger than a Vive and very close to the Reverb at 114°.
Thanks for explaining, I’ll give ETS2 tweaking a try … once I feel motivated enough. 