Should definitely load it from an ini or settings file or whatever; but hardcoded values was quick. I think the rest of the repo shows that I happily ignored most of the “sensible” coding principles along the way! 
Oh, I should add that this Heretic Project was a huge inspiration: Heretic in MonoGame (Wolf3D style raycasting) - Showcase - Community | MonoGame So, thanks @u2roka!