I wanted to post a picture of the time when I tried it, but it didn't show up because I had a very busy print with a variegated thread & there wasn't enough contrast between the thread & the fabric. I would use a thicker thread (28wt) and pick something MUCH darker than the fabric -- plus, try it out on scraps first. I would either use a very dark shade of pink, a deep red, or black. That dark red/pink color from the paisley fabric could be a good choice. I do something similar to PaperPrincess. I get a roll of calculator/register tape at the Dollar Store & make that as long as the area I want to quilt, then I fold it in half & in half again & keep going until I have enough spaces for all my letters. That way I can fit whatever I want -- within reason -- in a given space.
Since it's a kid's quilt & will be washed, I would go ahead & use a marker to write out the text as a rough guide to follow. Doesn't matter if you actually hit the lines or not, but it will give you an idea of how big to make them. I like the Crayola Ultra Clean markers because they are dark & always come out completely with cold water & a bit of soap, but anything you like (even a Hera marker) -- or the Golden Threads paper -- will work. At a minimum, I would draw the top & bottom lines since it's very difficult to maintain a straight line when writing/quilt writing.
