diff --git a/align/cmdline.py b/align/cmdline.py
index daa7e9f1e..dfe645afb 100644
--- a/align/cmdline.py
+++ b/align/cmdline.py
@@ -52,7 +52,7 @@ def __init__(self, *args, **kwargs):
         parser.add_argument("-n",
                             "--nvariants",
                             type=int,
-                            default=1,
+                            default=4,
                             help='Number of layout candidates to (attempt to) generate')
         parser.add_argument("-e",
                             "--effort",
@@ -102,7 +102,7 @@ def __init__(self, *args, **kwargs):
 
         parser.add_argument('--router_mode',
                             type=str,
-                            default='top_down',
+                            default='bottom_up',
                             choices=['top_down','bottom_up','collect_pins','no_op'],
                             help='Router mode')
 
@@ -111,7 +111,7 @@ def __init__(self, *args, **kwargs):
                             help='Run in GUI mode')
 
         parser.add_argument('--skipGDS',
-                            action='store_true',
+                            action='store_false',
                             help='Don\'t generate GDS files.')
 
         parser.add_argument('--lambda_coeff',
diff --git a/align/pnr/write_constraint.py b/align/pnr/write_constraint.py
index dd5219b34..77d68b7b6 100644
--- a/align/pnr/write_constraint.py
+++ b/align/pnr/write_constraint.py
@@ -67,7 +67,8 @@ def map_valid_const(self, all_const, module):
                 del const['instances']
 
             # Exclude constraints not to be exposed to PnR
-            if const['const_name'] in ['DoNotIdentify', 'GroupBlocks', 'DoNotUseLib', 'ConfigureCompiler', 'SameTemplate', 'PlaceOnBoundary']:
+            skip_constraints = {'DoNotIdentify', 'GroupBlocks', 'DoNotUseLib', 'ConfigureCompiler', 'SameTemplate', 'PlaceOnBoundary'}
+            if const['const_name'] in skip_constraints:
                 continue
 
             # Exclude constraints that need to be to multiple constraints