Jazzy,
I know this isn't what you want to hear, but it's hard for me to say. Let me explain.
My D25 is a beautiful guitar without a doubt, Guildmark (very talented and knowledgeable) has played her a couple of times, and he likes her. The finish on her is almost mint, but as a child, I abused her. When I was in my early 20's, I'd go on these weekend long camping trips during the summers, and do really stupid things, like leave her in a tent, trunk of a car, etc. In Texas, summer days often exceed 100 degress, and in the trunk of a car? Now, at 50 I shudder to think. Anyway, she's had a bit of bridge pull from the bottom for over 25 years, it's never moved mind you, but it does raise the action. Some say that extreme heat will loosen the glue in the neckblock and it will never be right without a neck reset. I don't know enough about guitar repair to comment about that, but it certainly makes sense to me. Needless to say, to me, the action is a touch high, and if you look down the neck from the top, you can make out an ever so slight bend around the 3rd fret. That's why I tweeked the neck, in an effort to get that bit of bend out, and hope the action was lowered a tad in the process. She's still got plenty of saddle, so I can go that route if I choose.
As far as results? If there are any from my very, very slight loosening of the nut, I don't see any. Maybe someone with a keener ear and eye might, but I'm half deaf and blind. My D25 has the most sentimental value, being my first and only new Guild, but it's the least valuable monetarily speaking, so she's my guinea pig.
West