I have not found a site that tells you how to do it in 3D Pro (which I have as well).
But as a general rule you digitise 2 or 3 layers at different angles, say 45 and 135 degrees for two layers, 0, 60 and 120 for three. Use a low density, set that in Preferences before you start each layer - you can go to 15 - and use narrow satin stitch outlines. Try something simple like a square or a heart shape, digitise a few with different settings, stitch them out, remove the wss and see what you've got. Compare that to your favourite FSL design - and you know which setting to choose. Really, digitising FSL is a matter of trial and error: keep a record of your samples - I use an oldfashioned card file : stick the sample on it and write down the settings you used. Try different fillings - #1 is a nice background to start with, embellish it with motive stitches.
Have fun trying
And no, I did not digitise my red hat in 3D, but used Embird as I find it easier to change parameters in Embird than change settings in 3D.
Can someone repost this? I really thought someone would have some ideas for me. Thanks in advance.