diff --git a/tableshift/models/compat.py b/tableshift/models/compat.py
index 5e8712ebc7..7f4f2e3d28 100644
--- a/tableshift/models/compat.py
+++ b/tableshift/models/compat.py
@@ -140,7 +140,10 @@ def is_domain_adaptation_model_name(model_name: str) -> bool:
 def is_pytorch_model_name(model: str) -> bool:
     """Helper function to determine whether a model name is a pytorch model.
 
-    ISee description of is_pytorch_model() above."""
+    See description of is_pytorch_model() above."""
+    if model=="catboost":
+        logging.warning("Catboost models are not suported in Ray hyperparameter training."
+                        " Instead, use the provided catboost-specific script.")
     is_sklearn = model in SKLEARN_MODEL_NAMES
     is_pt = model in PYTORCH_MODEL_NAMES
     assert is_sklearn or is_pt, f"unknown model name {model}"
diff --git a/tableshift/models/default_hparams.py b/tableshift/models/default_hparams.py
index d31782ccf1..27e8d79a47 100644
--- a/tableshift/models/default_hparams.py
+++ b/tableshift/models/default_hparams.py
@@ -140,14 +140,15 @@
 
 
 def get_default_config(model: str, dset: TabularDataset) -> dict:
-    """Get a default config for a model by name."""
+    """Get a default config for a model, by name."""
     config = _DEFAULT_CONFIGS.get(model, {})
+    model_is_pt = is_pytorch_model_name(model)
 
     d_in = dset.X_shape[1]
-    if is_pytorch_model_name(model) and model != "ft_transformer":
+    if model_is_pt and model != "ft_transformer":
         config.update({"d_in": d_in,
                        "activation": "ReLU"})
-    elif is_pytorch_model_name(model):
+    elif model_is_pt:
         config.update({"n_num_features": d_in})
 
     if model in ("tabtransformer", "saint"):
@@ -155,7 +156,7 @@ def get_default_config(model: str, dset: TabularDataset) -> dict:
         config["cat_idxs"] = cat_idxs
         config["categories"] = [2] * len(cat_idxs)
 
-    # Models that use non-cross-entropy training objectives.
+    # Set the training objective and any associated hypperparameters.
     if model == "dro":
         config["criterion"] = DROLoss(size=config["size"],
                                       reg=config["reg"],
@@ -170,10 +171,10 @@ def get_default_config(model: str, dset: TabularDataset) -> dict:
         config["criterion"] = GroupDROLoss(n_groups=2)
 
 
-    else:
+    elif model_is_pt:
         config["criterion"] = F.binary_cross_entropy_with_logits
 
-    if is_pytorch_model_name(model) and model != "dann":
+    if model_is_pt and model != "dann":
         # Note: for DANN model, lr and weight decay are set separately for D
         # and G.
         config.update({"lr": 0.01,
@@ -182,9 +183,9 @@ def get_default_config(model: str, dset: TabularDataset) -> dict:
 
     # Do not overwrite batch size or epochs if they are set in the default
     # config for the model.
-    if "batch_size" not in config:
+    if "batch_size" not in config and model_is_pt:
         config["batch_size"] = DEFAULT_BATCH_SIZE
-    if "n_epochs" not in config:
+    if "n_epochs" not in config and model_is_pt:
         config["n_epochs"] = 1
 
     if model == "saint" and d_in > 100:
diff --git a/tableshift/models/torchutils.py b/tableshift/models/torchutils.py
index c960d5d152..a2d30e7c88 100644
--- a/tableshift/models/torchutils.py
+++ b/tableshift/models/torchutils.py
@@ -69,12 +69,16 @@ def apply_model(model: torch.nn.Module, x):
 
 
 @torch.no_grad()
-def get_predictions_and_labels(model, loader, device, as_logits=False) -> Tuple[
+def get_predictions_and_labels(model, loader, device=None, as_logits=False) -> Tuple[
     np.ndarray, np.ndarray]:
     """Get the predictions (as logits, or probabilities) and labels."""
     prediction = []
     label = []
 
+    if not device:
+        device = f"cuda:{torch.cuda.current_device()}" \
+        if torch.cuda.is_available() else "cpu"
+
     modelname = model.__class__.__name__
     for batch in tqdm(loader, desc=f"{modelname}:getpreds"):
         batch_x, batch_y, _, _ = unpack_batch(batch)
diff --git a/tableshift/models/training.py b/tableshift/models/training.py
index 7f20f5f9aa..f129481e0b 100644
--- a/tableshift/models/training.py
+++ b/tableshift/models/training.py
@@ -120,10 +120,13 @@ def get_eval_loaders(
 
 
 def _train_pytorch(estimator: SklearnStylePytorchModel, dset: TabularDataset,
-                   device: str,
                    config=PYTORCH_DEFAULTS,
+                   device: str=None,
                    tune_report_split: str = None):
     """Helper function to train a pytorch estimator."""
+    if not device:
+        device = f"cuda:{torch.cuda.current_device()}" \
+             if torch.cuda.is_available() else "cpu"
     logging.debug(f"config is {config}")
     logging.debug(f"estimator is of type {type(estimator)}")
     logging.debug(f"dset name is {dset.name}")
diff --git a/tableshift/models/utils.py b/tableshift/models/utils.py
index 95dcb87357..cda392692b 100644
--- a/tableshift/models/utils.py
+++ b/tableshift/models/utils.py
@@ -22,7 +22,21 @@
 from tableshift.models.wcs import WeightedCovariateShiftClassifier
 
 
-def get_estimator(model, d_out=1, **kwargs):
+def get_estimator(model:str, d_out=1, **kwargs):
+    """
+    Fetch an estimator for training.
+
+    Args:
+        model: the string name of the model to use.
+        d_out: output dimension of the model (set to 1 for binary classification).
+        kwargs: named arguments to pass to the model's class constructor. These
+            vary by model; for more details see below. Note that only a specific
+            subset of the kwargs will be used; passing arbitrary kwargs not accepted by
+            the model's class constructor will result in those kwargs being ignored.
+    Returns:
+        An instance of the class specified by the `model` string, with
+            any hyperparameters set according to kwargs.
+    """
     if model == "aldro":
         assert d_out == 1, "assume binary classification."
         return AdversarialLabelDROModel(