My thought is the tighter wrapped one burnt the sugar because the foil transfered the heat more, the looser one let the moisture do its thing.
Now my two cents says loose the foil cut back on sugary rubs and cook around 250-275deg until it passes the bend test (lift rack from one end if it bends 90deg it's done) or toothpick test (toothpick goes in real easy) you should find you like them a lot and if you want sweet brush them with your favorite BBQ sauce about 15 minutes before they are done.
