From my own personal experience with making FSL (it IS one of my
faves to make) the following are the steps that I take.
1) start with a microtex or sharp LARGE eye embroidery needle
2) slow your machine down as slow as you can
3) 2-3 layers of a fibrous (not a "plastic" like texture) i use either or the
following Floriani Wet n Gone or Pellon 541 Wash n Gone (they have pretty
much the same texture)
4) I pretty much ONLY use Floriani thread for all my embroidery.
Hope you find a solution that works best for you.