Carla P

Lots of very good questions!! First of all, always start a new technique on a practice square. This is where you will train your brain and hands to work as a team without much effort. Before sitting down to your practice square, doodle out your designs on paper, a chalk board, a dry erase board (this is my favorite... plenty of room, erase and start over, and lay it down on the table so it is in the same position as your quilt), or a magna-doodle type toy. This trains your hands to move in different directions & helps your brain to begin memorizing the patterns. This is an invaluable warming up part of the process, but it is also a way to get into the habbit of sketching out designs that catch your eye during the course of each day for later use. (Trust me, you will forget them by the time you return home, and you'll drive yourself nuts trying to remember.)

Second, I have machine quilted on a domestic home machine for many years. I did recently purchase a long-arm, but I sat in front of my home machine enough years to learn to overcome every obstacle that came my way, or give up quilting, which wasn't an option. I'm not very good at explaining things sometimes, but I'll do my best to tell you what works for me. First of all, I turned my machine sideways with the sewing head facing me. You can see what is going on much better this way. The next thing I did was cut the front out of my presser foot, so it is shaped like a "C". This too will allow for better visability. If this step makes you a bit too nervous, you can use a clear foot or purchase a foot for your machine either made in the "C" shape or with the front already cut out; there are some on Ebay I believe. Make sure thet you have plenty of level space to both the left and right of the needle (with the machine turned sideways) by using books on each side of the machine, making a "table" like some of the ones posted on this site, or purchasing one. Either way will be effective since it is not so much for your hands, but to allow you access to your immediate quilting area. As always, support the bulk of your quilt so as to avoid drag. For large quilts, and yes I'm including King size in this and yes I've done them on the home machine, get a rod/pole like a 1/2 inch dowell, about 12 to 18 inches long to roll your quilt onto. (You could even roll a papertowel tube really tight & wrap it with masking or DUCT tape... in case you're curious Tim.)I have tried the bike clips, accordion folding, bunching, and many other methods and found this to be the best for me. The object is to get a tight roll that is easy to continue rolling in the neck area of your machine. Since it is not beside you, it is out of your way. You should never be worried about trying to actually quilt an area bigger than the space under your hands. Keep the quilt around your machine loose enough to move easily under your hands, and you'll be just as successful with a king size as you are on a baby quilt.
Practice moving your hands in every direction. You will naturally be more comfortable pushing the quilt away from you, but you will be doing yourself a favor to become comfortable sewing in all directions.
The ruler she (Karen McTavish) was using is for quilting straight lines with a long-arm. These machines do not have feed dogs, and you can not use a walking foot on them. Most people are incapable of sewing a straight line without a guide of some sort, and believe it or not, it is much more difficult to master the control over the machine than to master the control over the quilt, since the machine moves and not the quilt. Don't get me wrong, there are some advantages of the long-arm, but the home machine is capable of all of the same functions once you master the quilt. I have never taken any classes to learn quilting, because I don't have time, but Amazon loves me!! I read, a lot, and watch the DVDs available on the market. I have learned from some of the best teachers in the world, all from the comfort of my home. Best of all, I can pause, rewind, practice, cuss, watch again, and again & cook dinner all at the same time. My point is, do what works for you, which is, after all, the way many new best methods are born... because someone did what worked for them.
Lastly, I am sorry, but I can not answer the question about adding a sashing after quilting, because I have limited experience (none) with quilt as you go type methods, which this might be a version of, or could be if you wanted to. I hope someone else can answer this for you.

Sorry if I went on too long, and I hope something I've written here will be of some use to someone.
Take care,
Carla P