The distance to you for world generation is probably the same distance as triggering of the Trader in the world. Honestly all these in game "measurements" are kind of meaningless without some actual point of reference that is in scale to it.


In terms of the "sphere" theory I actually tried to build over a trader... it isn't actually the sphere you see it is more of a cone with very sheer walls and what must be a super high point. It did taper in a bit as it went up but could only go so far.