Wool yarns or silk yarns

I have been busy finishing up this piece, putting on a backing, inserting a zipper (not my forte, alas).  But I haven't been sitting around just reading or enjoying the last of the summer or babysitting...oh no wait, yes I have!!  We've been having the most glorious weather.  And in between all of that, I've been stitching.

In this portion of the pillow (yes, it has been determined by the future recipients that this is to be a pillow) I have used a silk thread (golden yellow) at the top of this pic for the hand stitching and in the bottom portion I have used a wool/poly thread.  I am trying to decide which I prefer.  I think at this point I favour the wool mix.  Perhaps it's because the silk seems to be sitting on top of the fabric (no doubt because of the way I've stitched it) whereas the wool seems to meld a bit more into the fabric, as it might do when it is felted. But I won't decide definitively based on this small sampling.....I'd best get busy and work up a few more designs to practice with. I have lots of ideas so I have to get going.....

I'll be back.