I don't think any fill is needed.

After looking at the samples Jan showed us, I think I like the stippling look best.

I agree with this...the pattern is beautiful the stippling would muddy the water IMHO..

I personally think there is enough going on already (beautiful) so I would not do any more to it once the feathers are quilted.

I agree with ManiacQuilter above. Do the feathers first and then see if additional quilting is necessary. Looking at the top now, I would think the feathers would be sufficient and anything else would detract from this beautiful design. Do the feathers and then reevaluate. Just me!!

I vote for the grid. Your quilt will be awesome. Be sure to share your finished product with us.

grid of one inch or more.

Why do you need more stitching. I think it would take away from the beauty of the feathers. IMHO.

For the dissenters of "fill"---this design looks like it would be "enough" quilting, BUT, if you don't follow up with
background "fill", the parts that have no quilting will puff up and make it difficult to see the lovely feathers.
Something to consider. If you add a tiny hand stipple after all the feathers are quilted, you will not have to premark.
If you go with a 1/2" grid you will need to mark it before any quilting is done or you'll have a hard time keeping the lines
from appearing to wobble as they go across the quilt. In fact, I always mark background grids before layering.

dog mama: What type of marking pen/pencil did you use? That is sure a lot of handwork and it is going to be beautiful when it's done. Good Luck and Happy Quilting.