Gay

I wouldn't be concerned with matching up with the colour system of any machine, or digitising program for that matter, as they all have their own 'formulas' for displaying shades, and one brand is not the same as another - it's a technical thing. Whatever colour the design is saved in, you will use the colour you like. I would also recommend using colour catchers when washing, as some threads do run. I've just had some hand dyed red thread run on a white fabric.

Peckish

This doesn't work with our modern synthetic dyes. Sorry.

cashs_mom

I would agree with not using rayon thread. I embroidered some sheets years ago when I go a machine with fancy stitches. I used rayon and it looked great. However, with repeated washings it did fad out badly. Also rayon thread just doesn't hold up as well. Stick with the poly.