On the F/P video, she precut little rectangles, then sewed them to her foundation (muslin), then trimmed to the foundation. I thought she lost a lot of tie fabric when she trimmed.
One thought. Pick your finished block size 6" (or 8"-whatever). Add your seam allowance 6-1/2 (8-1/2) Then double it to 13" (17"). Cut your muslin to 13" (17"). take your ties apart, sew to your muslin. Then trim the edges, then cut your muslin into 4 pieces, back down to your block size 6-1/2" (8-1/2"). Ties are LONG and will fit this larger foundation, then you reduce the amount of trimmings by half.