I lap hoop is about 13" across. I have never used a floor frame of any type for the reason mentioned above...think it would be very uncomfortable. I can sit however I like in my comfy chair and quilt until my fingers bleed! I have done from baby to king size quilts in my hoop. Sometimes I use no hoop at all but actually prefer it as it makes it easier to find where I've left off quilting! As Jan in VA mentioned, there is no tension used in a quilting hoop so you can do a 'rocking' stitch - your sandwich is quite loose in the hoop unlike embroidery.
Another item you'll need to test drive is a thimble. Most commercially available thimbles have a recessed top with very shallow dimples. You push with the top of your finger. I use a Thimblelady (
www.thimblelady.com) thimble. Cone shaped; open top; deep dimples on the side so that you are pushing with the pad/side of your finger. I find this more comfortable than pushing with the top of my finger.
And then there are needles. My preference is Roxanne #11 betweens. Find they stay sharp; don't bend easily; allow me to get nice, small, even stitches.
Others will weigh in with their preferences I'm sure. All of these elements are personal preference. Find the combo that works best for you.