Think out of the block. I have quilted as I go many times and have never been disappointed in do so. Some of my prettiest designs have come from them. Sashing is no problem; don't do as you make the blocks, but after all blocks are finished. This way you'll be able to see the "picture" more clearly. If you have to fill in any places before sashing best to do it this way - that's my suggestion. Like I said in the beginning, "Think out of the block" - be your own quilter, not copying someone else's design. Enjoy. God gave you the talent to quilt - use it. In fact, the Holy Spirit has designed the quilts I make. He is more talented than us all put together. God bless, and may this Christmas be filled with the Fruits of the Spirit (Galatians 5:22-23).