I use signature on my longarm and never have had a prob with it......but, on any cotton threD, the darker the color the more dye is used and therefore if you thread is dark, it may be weaker....also when doing a diagonal line it is better not to go from top to bottom, but instead do a kind of peaks and valleys.......less stress on that line of stitching.....so I do WWWW across a row, then another connecting those WWWWWW across...... As far as binding who knows. But if you are using serger thread STOP and use regular as mentioned above not meant for regular sewing....jmho