What have you read about it that has caused you to stop considering it, or to overlook it from the start?
This response seems unlikely to be a crux for you, but I don’t often see it written explicitly, so I’ll mention it anyway in case someone reading hasn’t thought of it:
Negative utilitarianism implies that you would prefer to destroy a universe with an unbounded amount of certain positive experience, if that would prevent an infinitesimal chance of one speck of dust getting in someone’s eye.
This means that a negative utilitarian will basically always prefer that the universe is destroyed, since there will always (I suspect) be uncertainty about which things suffer (1 is not a probability).
This response seems unlikely to be a crux for you, but I don’t often see it written explicitly, so I’ll mention it anyway in case someone reading hasn’t thought of it:
Negative utilitarianism implies that you would prefer to destroy a universe with an unbounded amount of certain positive experience, if that would prevent an infinitesimal chance of one speck of dust getting in someone’s eye.
This means that a negative utilitarian will basically always prefer that the universe is destroyed, since there will always (I suspect) be uncertainty about which things suffer (1 is not a probability).