I had this problem, too. Using a spider helped, especially for triangles with those little points. After stumbling upon Bonnie Hunter's site, I still continued with the spider theory but started using quilt pieces instead. Now instead of wasting the time and thread I am working on two quilts at once. The one I'm working on with leaders and enders isn't the one I'm primarily working on, but if you are sewing anyway you might as well make it count, right? It can be the beginning of the next quilt that you'll "upgrade" to the main quilt or just stay a leader/ender project until it's finished.
And yes, 1/4" seam is correct. It seems so tiny after sewing garments and home dec, doesn't it? A bigger seam will only add bulk for the quilting process later, and the quilting will make it more secure. You'll be anchoring the pieces to the back, so there won't be as much stress on each seam like there is with other sewing.