sugars go to the bottom right? well do i take reading after racking when sugars are mixed up nice, or before rack when all sugar is at bottom? I have been getting different readings by just waiting a few moments.
Are you asking about taking a gravity reading prior to racking to secondary?
That's the way I read it...
If you're brewing an extract, and topping off your fermenter with water, you will see different readings at the top of the fermenter, compared to the bottom, when things aren't mixed well.
By the time your primary fermentation is complete, you don't have to worry about top of the bucket vs. bottom. If you use a wine thief, your sample will come from lower in the fermenter anyway.
Some of the pro's use a refractometer instead of a hydrometer.
I can't speak to that.