Also - if you haven't calibrated your hydrometer you might want to do that as well to verify your reading. But definitely you are looking for stability as well.
Don't know what you are seeing - but the sludge at the bottom of my bottles is due to yeast settling after carbonation. And I need the yeast to carbonate beer in the bottle.
The good news: you don't have to worry about the carbonation level. If you used the right amount of sugar the length of time you boil doesn't matter.
The bad news...well...there is always the risk of an infection. You just increased the risk is all.
Ummm. If you have any extras that you can't get around to drinking ... Well it wouldn't be right if we didn't offer to take those nasty, awful beers off your hands. :mug:
The real problem is gonna be this: it will be the best beer you have ever tasted! And you will spend years trying to duplicate the recipe ... And never will! Lol.