I agree 100% with Oregongirl about the basting. Personally, I use both spray and hand basting, and always work from the center out, both with the basting and the quilting. With the water soluble thread (not recommended for swimwear), you can stabilize and then remove most of the basting, which can get in the way sometimes. WS thread is not a necessity; it just sometimes frees one up a bit. There are lots of ways to baste; my best advice is to leave the thread 'sans knot.' If there is a knot, it will not remove as easily, especially when it gets caught in the foot (major bunching).
ps: using the WS thread is an accompaniment to basting, not a replacement for it.