diff --git a/garlic/exp/nbody/tampi.nix b/garlic/exp/nbody/tampi.nix
index a245110..2ea6b41 100644
--- a/garlic/exp/nbody/tampi.nix
+++ b/garlic/exp/nbody/tampi.nix
@@ -8,6 +8,7 @@
 
 # Leave the first CPU per socket unused?
 , freeCpu ? false
+, particles ? 1024 * 32
 }:
 
 with stdenv.lib;
@@ -25,7 +26,7 @@ let
   genConf = with bsc; c: targetMachine.config // rec {
     inherit (machineConfig) hw;
     # nbody options
-    particles = 1024 * 32;
+    inherit particles;
     timesteps = 10;
     inherit (c) nblocks;
     totalTasks = ntasksPerNode * nodes;
diff --git a/overlay.nix b/overlay.nix
index 1761928..0c54406 100644
--- a/overlay.nix
+++ b/overlay.nix
@@ -282,13 +282,12 @@ let
         nbody = rec {
           test  = callPackage ./garlic/exp/nbody/test.nix { };
           tampi = callPackage ./garlic/exp/nbody/tampi.nix { };
-          baseline = tampi;
-          freeCpu = callPackage ./garlic/exp/nbody/tampi.nix {
-            freeCpu = true;
-          };
-          jemalloc = callPackage ./garlic/exp/nbody/tampi.nix {
-            enableJemalloc = true;
-          };
+
+          # Experiment variants
+          medium = tampi.override { particles = 64 * 1024; };
+          baseline = medium;
+          freeCpu = baseline.override { freeCpu = true; };
+          jemalloc = baseline.override { enableJemalloc = true; };
         };
 
         saiph = {