diff --git a/p256/tests/projective.proptest-regressions b/p256/tests/projective.proptest-regressions
index b332dce68..dc9f6ab50 100644
--- a/p256/tests/projective.proptest-regressions
+++ b/p256/tests/projective.proptest-regressions
@@ -5,3 +5,4 @@
 # It is recommended to check this file in to source control so that
 # everyone who runs the test benefits from these saved cases.
 cc e19ee42c127b7289fbe7e42df47abf141eb644afcbd13ac141e39b9960362174 # shrinks to point = ProjectivePoint { x: FieldElement(0x823CD15F6DD3C71933565064513A6B2BD183E554C6A08622F713EBBBFACE98BE), y: FieldElement(0x55DF5D5850F47BAD82149139979369FE498A9022A412B5E0BEDD2CFC21C3ED91), z: FieldElement(0x4FE342E2FE1A7F9B8EE7EB4A7C0F9E162BCE33576B315ECECBB6406837BF51F5) }, scalar = Scalar(0x0000000000000000000000000000000000000000000000000000000000000001)
+cc 67d76546dee30db7f75f666ed335f84d90da4ce8775d612dcdb88a3058ef7071 # shrinks to point = ProjectivePoint { x: FieldElement(0x823CD15F6DD3C71933565064513A6B2BD183E554C6A08622F713EBBBFACE98BE), y: FieldElement(0x55DF5D5850F47BAD82149139979369FE498A9022A412B5E0BEDD2CFC21C3ED91), z: FieldElement(0x4FE342E2FE1A7F9B8EE7EB4A7C0F9E162BCE33576B315ECECBB6406837BF51F5) }, scalar = Scalar(0xAE74000000000000000000000000000000000000000000000000000000000000)
diff --git a/primeorder/src/projective.rs b/primeorder/src/projective.rs
index 5a621dd92..17c304810 100644
--- a/primeorder/src/projective.rs
+++ b/primeorder/src/projective.rs
@@ -605,7 +605,25 @@ where
     FieldBytes<C>: Copy,
 {
     fn recommended_wnaf_for_num_scalars(num_scalars: usize) -> usize {
-        todo!()
+        // Empirical heuristic from the zcash/bellman implementation.
+        if num_scalars >= 32 {
+            3
+        } else if num_scalars >= 1 {
+            2
+        } else {
+            4
+        }
+    }
+
+    fn scalar_repr_to_le_bytes(
+        repr: &<Scalar<C> as PrimeField>::Repr,
+    ) -> Vec<u8> {
+        // SEC1/NIST curves use big-endian scalar representations;
+        // reverse to get little-endian for wNAF decomposition.
+        let mut le: Vec<u8> =
+            AsRef::<[u8]>::as_ref(repr).to_vec();
+        le.reverse();
+        le
     }
 }