I run a thermion xm38. Was also worried about the limited fov with the 4x. What i find is the fov isnt as critical using thermal because of the contrast image, it picks up quick. . I think its harder to pick up a yote in a cut cornfield on 3x day time than it is with the thermal at 4x. Ideally the a 640 scope with a 3x base would be ideal but ive shot at 13 coyotes this year with the xm , they all dead. Good luck.