Ok, I threatened to do this one next and against the advise of others (you know who you are!) I decided to go with the flannel back even though I was warned that it was more difficult to FMQ. Turns out that I didn't have that much trouble with it.
For some reason I still much prefer the wide, swoopy meanderings to the tight, perfect, tiny stippling. The ones that have the tiny stippling feel so much stiffer and smooshed than the wider, fluffier alternative. But that's just me...
I had to go with the red thread, which was certainly taking a chance...every little stitch shows, but I do kind of like the below block if for no other reason than it started to look like a dog outline as I stared at it...you know, like when you stare at the clouds and shapes appear?
The red thread did also help fill in the many blanks areas, too.