I cannot get down on the floor either so figured a way to use my cutting table.
This is for up to lap top size, larger quilt tops I send out.
I use those white table clips that slide over the edge of the table. You can use those big black clips for office use. But they are bulkey.
I do stretch the backing a little as I clip around the table.
If the quilt is bigger than the table I do it in two stages, unclip and move for second section.
I lay the 80/20 batting on top of backing and smooth out.
Lay the top on and stretch a little as I clip it on. Then I pin it with bent pins. I used the spray a few times but it is riskey when you have to do your quilt in sections.
Once it is pinned then I unclip and move the quilt for the next section and clip again. So far it has worked out for me this way.
I bought my cutting table at Joanns for around 50 dollars and worth every penny. The clips are made for the one inch depth of the table.
It is only 35 inches wide so have to move the quilt to do it all.