These needles, by Superior, are titanium-coated and are guaranteed to last 5-8 times longer than regular needles. 

Topstitch needles have an eye specially designed for heavy threads. I like to poke the smallest hole possible so I start with a 90/14 topstitch needle and if I don't get great results, I use the 100/16 topstitch needle. (If you only want to purchase one pack, go with 100/16.)

WonderFil Spagetti 12wt cotton thread stitches beautifully with these needles. Most machines prefer regular 50-60wt cotton bobbin thread with this in the needle.