I've never actually had to deal with a scriff-infected object so large and so close that it was not effectively less than one degree. Even a car fifty yards distant is not going to have a larger target radius than "that way". A star destroyer might be a pretty big object, but even the moon is not that big in terms of vector diameter as sensed from earth.
Note that if you have one object ten feet distant and another ten miles distant but they happen to be on the same exact line, you've only got one vector. (I used this in one world to create a straight line direction finder. There was an intermittent sense in a constant direction, so I placed two objects about fifty yards apart such that they and the target vector would be on the same line, and then I walked that line by keeping a single sense impression behind me until I came to the target.) Since that's the case, the number of objects is irrelevant.
For what it's worth, the sense tends to point toward the middle of the object, but if you were right up against it you could probably sense its dimensions, if your pointing would sweep some significant distance. Remember, though, that you only have the sense when you relax.
As to being surrounded by one of your possessions, that's a bit trickier. Obviously that happens if, for example, you are in your car or your spaceship. But then, you are usually in your clothes, and these don't interfere with your ability to sense objects beyond that. So I would say that as long as it's on person it doesn't really register, but if it surrounds you independent of yourself you have something more like a vector plane or dome, or even you have the sense of being completely surrounded by your equipment, like you left something in every direction.
It would also obscure objects in the same plane or vector, regardless of whether they are in front of or behind it.
--M. J. Young