I have found Upholsterers Needles that have a sort of flat spot right near the tip of the point that works well. I think I found them at Walmart. I have tried the curved needles, but really don't like them....it's a preference thing.
Tying quilts is a practice, practice,practice thing. Just gotta keep at it. I also use the DMZ floss. I use the whole strand (i know some that only use a couple threads) When I tie, I use DOUBLE thread and make a square knot on it. Seems to be the only knot that will stay. Have tried just plain tying it, but the knots come out.