I suppose it may end up costing a bit more, but it'll be a lot quicker and easier to make. Assuming that yarn colours are reasonably consistent, and that any small variations wouldn't be enough to show up in quilting (presumably it would be different if I were actually crocheting with the yarn), I could probably get away with buying the thread as I need it. Right now I'm not 100% sure of the colour, so I may order one ball of that colour, a few balls in other colours so that I can start building up a good stash of this thread, and then I can always try another colour if I don't get on with the first one. I've just done the one quilt with perle #8 so far but I really like it, both in that it's quicker and easier to sew, and in that it shows off the quilting very nicely.
Does anyone have an opinion on the thread colour?