diff --git a/dedalus/core/arithmetic.py b/dedalus/core/arithmetic.py
index 8a13366a..a3ee79a5 100644
--- a/dedalus/core/arithmetic.py
+++ b/dedalus/core/arithmetic.py
@@ -691,7 +691,7 @@ def __init__(self, arg0, arg1, out=None, **kw):
         if arg0.tensorsig[0].dim != 3:
             raise ValueError("CrossProduct requires 3-component vector fields.")
         # FutureField requirements
-        self.domain = Domain(arg0.dist, self._build_bases(arg0, arg1))
+        self.domain = Domain(arg0.dist, self._build_bases(arg0, arg1, **kw))
         self.tensorsig = arg0.tensorsig
         self.dtype = np.result_type(arg0.dtype, arg1.dtype)
         # Setup ghost broadcasting
diff --git a/dedalus/core/basis.py b/dedalus/core/basis.py
index 0791f470..68ba5a6e 100644
--- a/dedalus/core/basis.py
+++ b/dedalus/core/basis.py
@@ -533,8 +533,9 @@ def __mul__(self, other):
             return self
         if isinstance(other, Jacobi):
             if self.grid_params == other.grid_params:
-                # Everything matches except size, a, b
+                # Take maximum size
                 size = max(self.size, other.size)
+                # Take grid (a0, b0) for minimal conversions
                 a = self.a0
                 b = self.b0
                 return self.clone_with(size=size, a=a, b=b)
@@ -548,8 +549,9 @@ def __rmatmul__(self, other):
             return self
         if isinstance(other, Jacobi):
             if self.grid_params == other.grid_params:
-                # Everything matches except size, a, b
+                # Take maximum size
                 size = max(self.size, other.size)
+                # Take operand (a, b) for minimal conversions
                 a = self.a
                 b = self.b
                 return self.clone_with(size=size, a=a, b=b)