Question: " I wanted to tackle quilting a large size quilt under my domestic machine without stringing myself or disappearing under the mass of fabric while still trying to see the needle!"
I made very big quilts (90" square and bigger) on an old Bernina 1260 which has a small space under the arm.
Having your machine set down into a table is the biggest thing to help. You have so much more control and are comfortable because you are not sitting up 'begging' but can rest your forearms down on the table which feels good and gives you lots of control (I just spent a day at my son's place in London sewing on this old machine which was sat on a regular table - and my shoulder is still aching!).
My machine is set far back with 11+" from the front of the table to the needle point - arm rest/control space is created in front of the machine.
I do not spread the quilt out flat but have it bunched up all around, including on my knee. Flat it is immovable, bunched the quilt has less resistance and seems 'lighter' and freer. I just flatten the bit I am working on.
I do FMQ and not regular straight stitch. With FMQ you are only moving a small amount of the work and not the whole thing through the machine from top to bottom.
I use a teflon FMQ mat which really helps as do the hand grippers (non slip kitchen mat) I show in some of the classes.
I have the needle down function on at all times so that the line of stitches stays smooth and not jagged, and I reposition the work often.
I do not try and do long unbroken lines of stitch without ends, but do short complex designs that have a lot of stops and starts (easier to sew a short row well than a long one).
I unpick when it goes wrong.
I sew very slowly.
I really enjoy the process and the results.
Hope that helps you! Philippa :)