A 250 gram per breast reduction will need not relieve any musculoskeletal complaints. You would likely be a DD cup. This kind of a person with your statistics would be a lift and would never qualify for insurance purposes in New York. You would need a resection of at least 500-750 grams to make an appreciable and lasting difference.
It is very hard to predict the actual cup size you will have after a 250 cc removal from each side. In general, a cup change can be between 150-200 cc's for most people, but this a rough estimate and it will vary with height and weight, and overall body shape.