Hydrometers are notoriously inaccurate and need to be replaced every few months. First I'd recommend asking your LFS to test your salinity with a refractometer before you start to bring it down - it might not in fact be as high as your hydrometer is reading it. Second, I'd recommend buying a refractometer (they run about $50), which will be far more accurate to test your salinity!
If it is indeed that high, then you want to bring it down slowly - not more than .001 per day. As Jimboaf says, for a 65g, you can take out about 1g a day from your tank and replace it with RO/Di water. I am guessing that a gallon will change your salinity by about .001. In my 10g tank an 8oz glass changed my salinity by .001. If a gallon change doesn't bring it down that much, then up to 1.5 or 2g. You can drip it in over a few hours if you want, but I don't think its going to be a huge deal if you do it all at once. That said, what do you have for livestock? If you have any really fragile animals, then you should probably drip it. Ideally you want to bring your salinity down to about 1.025-1.026
And +1, don't top off with saltwater - just RO/DI.