So- I decided to make the shade before cutting and hemming the fabric. And I did!- the fabric did not leave the table until the shade was 90% complete. It's kind of backwards, but it ensured that the grain remained straight and eliminated distortion from hemming.
My awesome gridded fabric table cover made this possible.
The first step was to get the grain straight by pulling a thread across the entire width and beginning the cut there.
I rolled the fabric to the end of the table, smoothed it, and lined the selvedge up on one side and lined the fold up with the 60" grid line on the other side.
I was able to see the printed lines through the two layers, so I cut the top layer at 10" to create the 70" cut. I cut all the way to the end of the table and removed the leftover, keeping the fabric well weighted throughout. That gave me about 144" of my 215" and I left the roll intact at the far end.