diff --git a/sup3r/models/abstract.py b/sup3r/models/abstract.py
index 3ffc7098b4..4b48fa89f7 100644
--- a/sup3r/models/abstract.py
+++ b/sup3r/models/abstract.py
@@ -211,12 +211,14 @@ def s_enhance(self):
         model training during high res coarsening and also in forward pass
         routine to determine shape of needed exogenous data"""
         models = getattr(self, 'models', [self])
-        s_enhances = [m.meta['s_enhance'] for m in models]
+        s_enhances = [m.meta.get('s_enhance', None) for m in models]
         s_enhance = (
             self.get_s_enhance_from_layers()
             if any(s is None for s in s_enhances)
-            else np.prod(s_enhances)
+            else int(np.prod(s_enhances))
         )
+        if len(models) == 1:
+            self.meta['s_enhance'] = s_enhance
         return s_enhance
 
     @property
@@ -225,12 +227,14 @@ def t_enhance(self):
         model training during high res coarsening and also in forward pass
         routine to determine shape of needed exogenous data"""
         models = getattr(self, 'models', [self])
-        t_enhances = [m.meta['t_enhance'] for m in models]
+        t_enhances = [m.meta.get('t_enhance', None) for m in models]
         t_enhance = (
             self.get_t_enhance_from_layers()
             if any(t is None for t in t_enhances)
-            else np.prod(t_enhances)
+            else int(np.prod(t_enhances))
         )
+        if len(models) == 1:
+            self.meta['t_enhance'] = t_enhance
         return t_enhance
 
     @property
@@ -593,7 +597,7 @@ def save_params(self, out_dir):
             fp_params, 'w', encoding=locale.getpreferredencoding(False)
         ) as f:
             params = self.model_params
-            json.dump(params, f, sort_keys=True, indent=2)
+            json.dump(params, f, sort_keys=True, indent=2, default=safe_cast)
 
 
 # pylint: disable=E1101,W0201,E0203
diff --git a/sup3r/utilities/utilities.py b/sup3r/utilities/utilities.py
index 6d8bf4c512..3d7bf0a873 100644
--- a/sup3r/utilities/utilities.py
+++ b/sup3r/utilities/utilities.py
@@ -38,9 +38,9 @@ def safe_cast(o):
     return str(o)
 
 
-def safe_serialize(obj):
+def safe_serialize(obj, **kwargs):
     """json.dumps with non-serializable object handling."""
-    return json.dumps(obj, default=safe_cast)
+    return json.dumps(obj, default=safe_cast, **kwargs)
 
 
 class Timer: