I'd be surprised if a rigger would charge anything less than a half day. Depending upon where you are, you have to consider that you are paying for the travel time ... there's no way around that. No professional is paying for their own travel, not unless he is desperate for work or just plain being charitable. Aside from that, the rigger should be sure you are paying for a thorough job. If he goes up there for half an hour and doesn't pay any attention to other potential problems, do you think he is trusting you that you won't blame him for anything else that goes wrong? Why do you have a bad spreader ... do you think there might be some other problem? The rigger is probably thinking along those lines.
What if he says (just for argument) this will only take an hour, and he goes up there and finds 4 hours worth of problems. Is he going to do the work and then come down and argue with you for the extra time? I don't think so.
If you plan on hiring the rigger, pay his rate and demand that his work be comprehensive ... if he is any good, he will be charging you for comprehensive work (based on a defined scope) whether that is what you want or not. If he isn't any good, he may give in to your argument that the work should be cheaper.
If you don't want to pay the fair price (shop around if you think he's not fair) then have at it on your own.
Honestly, in NYC, how is anybody going to survive if they aren't charging at least $1,000 per day. No matter how small the job, you will chew up half a day of the guys time and it isn't guaranteed that the guy can bill 40 hours per week. I always find it absurd when people argue that the hourly rate should be similar to what you might think is a fair wage. $120 billed per hour isn't much when you have to work 60 hours a week to bill 40 hours and pay expenses.