Just did this up in EQ & it tells me for a 60 x 70 quilt you will need
background - 2 5/8 yds
strips - 4 yds darkt fabric and 7 1/2 light
extra needed for a border
This seems a lot to me but I hear EQ is very generous, & too much fabric is better than too little.
I'm guessing EQ gives you that much fabric for the paper piecing as it will take more than just strip piecing.