Definitely, definitely go to your Janome dealer and get yourself a walking foot! It will save you LOTS of frustration and help to prevent those little wrinkles in your quilting. As for the maximum distance between quilting lines, check the directions on the package of the batting you're using. It will tell you there how close it has to be quilted. I use Warm and Natural and it can be quilted up to 10 inches apart according to its directions. You have lots of options with your block. I love your colors. Your quilt will be beautiful. You can do this! Welcome to the board. :)