Laser cut 1 inch hexies.
Apliquick lightly fusible interfacing is perfect for this project. No need to remove the paper. When washed you will hardly know it's there.
Consider machine appliquéing you hexies together. Use a narrow blanket or zig zag stitch. 1.5 in width and0.3 in length with invisible thread. See thread category to order.
MonoPoly is a reduced-sheen polyester monofilament invisible thread. 2,200 yds. CLEAR. Great for invisible thread applications. MonoPoly is .004" (.1mm) in diameter (90 denier) = Very fine