I've not done this pattern nor is it in my stash, but the patterns I do have that use the blending filament all tell me to use one strand of filament and one strand of a color per stitch. I just finished a ship pattern where I had to use filament on some of the waves. Some of them blended with the white and some with blue. The pattern had a symbol assigned to each type of blend stitch to tell me whether to use blue or white. Is there any info in the instructions at all?

I believe this is a "Lavender and Lace" angel. I have not stitched this particular pattern, but have done 4 other L & L angel designs. If you look on your chart, does it show any directions ( usually they are located near the floss symbol " key" if there are any specific directions)? OR is the chart just showing the "symbol key" designating what areas to use the Silver blending filament?
If it only shows the symbol key for your Silver filament, I would suggest you try what I did with one of my angels:
1) take a short length (long enough to cross stitch 6-8 spaces) of The Silver filament ONLY and cross stitch using two strands of it where the pattern symbol states you are to stitch the filament; the perfect area would be if you have 6-8 of these stitches to do right next to each other (perhaps the hem of the angel's gown?) and where it will be easy for you to "frog" out the stitches. If you don't like how it looks, then carefully 'frog' out the filament, re- thread your needle with one strand of white floss and a strand of the silver filament and restitch the area. Which way do YOU think looks better?
That's what's nice about counted cross stitching; you can "change things". There aren't any "stitch police" that will come knocking. :)
PS: the angel pattern I did called for "gold" filament (no specific instructions, just the pattern symbol key for Kreinik gold filament, and when I tried both ways, as described above, I went with one strand of the filament to one strand of floss. :)

These L&L patterns are so gorgeous! :)