diff --git a/keymap/config.h b/keymap/config.h
index 32c68f3..656d6ba 100644
--- a/keymap/config.h
+++ b/keymap/config.h
@@ -31,6 +31,10 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 // Vial features
 #define DYNAMIC_KEYMAP_LAYER_COUNT 5
+// looks like this DYNAMIC_MACRO_SIZE doesn't change anything
 #define DYNAMIC_MACRO_SIZE 0
-#define VIAL_TAP_DANCE_ENTRIES 0
-#define VIAL_COMBO_ENTRIES 0
+/* 8 entries take only 6 bytes more than 2 entries
+   Thus, 8 and 0 are the only reasonable values. */ 
+#define VIAL_KEY_OVERRIDE_ENTRIES 8
+#define VIAL_TAP_DANCE_ENTRIES 8
+#define VIAL_COMBO_ENTRIES 8
diff --git a/keymap/rules.mk b/keymap/rules.mk
new file mode 100644
index 0000000..e55b1a6
--- /dev/null
+++ b/keymap/rules.mk
@@ -0,0 +1,43 @@
+VIA_ENABLE = yes
+VIAL_ENABLE = yes
+
+LTO_ENABLE = yes
+
+# 2952 bytes
+QMK_SETTINGS = no          # Vial tab
+# 2144 bytes
+MOUSEKEY_ENABLE = yes      # Mouse keys
+# 544 bytes
+EXTRAKEY_ENABLE = yes      # Audio control and System control
+
+# each of the following features take extra space
+# in three steps
+# - the QMK feature (enables here)
+# - the Vial feature (enabled if VIAL_XXX_ENTRIES > 0)
+# - each vial entry for the feature
+
+# qmk feature : 504 bytes
+# vial feature : there is no special setting
+DYNAMIC_MACRO_ENABLE = no
+
+# qmk feature : doesn't compile with
+#               VIAL_KEY_OVERRIDE_ENTRIES = 0 
+# with 1 vial entry   : 1696 bytes
+# with 2 vial entries : 1814 (+118)
+# with 3 vial entries : 1830 (+16)
+# with 8 vial entries : 1820 (-10) SIC
+KEY_OVERRIDE_ENABLE = no
+
+# 1676 bytes + 50 bytes each entry
+# qmk feature         : 696
+# with 1 vial entry   : 1676 (+980)
+# with 2 vial entries : 1720 (+44)
+# with 8 vial entries : 1714 (-6)
+TAP_DANCE_ENABLE = yes
+
+# 900 bytes + 
+# qmk feature         : 924
+# with 1 vial entry   : 1964 (+940)
+# with 2 vial entries : 2082 (+118)
+# with 8 vial entries : 2046 (-36)
+COMBO_ENABLE = yes
diff --git a/keymap/vial.json b/keymap/vial.json
new file mode 100644
index 0000000..3bc04d1
--- /dev/null
+++ b/keymap/vial.json
@@ -0,0 +1,28 @@
+{
+  "name": "Dactyl Manuform (5x6)",
+  "lighting": "none",
+  "matrix": { "rows": 12, "cols": 6 },
+  "layouts": {
+    "keymap": [
+      ["0,0", "0,1", "0,2", "0,3", "0,4", "0,5"],
+      ["1,0", "1,1", "1,2", "1,3", "1,4", "1,5"],
+      ["2,0", "2,1", "2,2", "2,3", "2,4", "2,5"],
+      ["3,0", "3,1", "3,2", "3,3", "3,4", "3,5"],
+
+      [{ "x": 12, "y": -4 }, "6,0", "6,1", "6,2", "6,3", "6,4", "6,5"],
+      [{ "x": 12 }, "7,0", "7,1", "7,2", "7,3", "7,4", "7,5"],
+      [{ "x": 12 }, "8,0", "8,1", "8,2", "8,3", "8,4", "8,5"],
+      [{ "x": 12 }, "9,0", "9,1", "9,2", "9,3", "9,4", "9,5"],
+
+      [{ "x": 2 }, "4,2", "4,3"],
+      [{ "x": 4 }, "4,4", "4,5"],
+      [{ "x": 6 }, "5,4", "5,5"],
+      [{ "x": 6 }, "5,2", "5,3"],
+
+      [{ "x": 14, "y": -4 }, "10,2", "10,3"],
+      [{ "x": 12 }, "10,0", "10,1"],
+      [{ "x": 10 }, "11,0", "11,1"],
+      [{ "x": 10 }, "11,2", "11,3"]
+    ]
+  }
+}
diff --git a/rules.mk b/rules.mk
deleted file mode 100644
index df8a156..0000000
--- a/rules.mk
+++ /dev/null
@@ -1,4 +0,0 @@
-VIA_ENABLE = yes
-VIAL_ENABLE = yes
-
-LTO_ENABLE = yes
diff --git a/vial.json b/vial.json
deleted file mode 100644
index 0875d0f..0000000
--- a/vial.json
+++ /dev/null
@@ -1,101 +0,0 @@
-{
-  "name": "Dactyl Manuform (5x6-5)",
-  "vendorId": "0x444D",
-  "productId": "0x3536",
-  "lighting": "none",
-  "matrix": {"rows": 12, "cols": 6},
-  "layouts": {
-    "keymap": [
-      [{"x": 3.5}, "0,3", {"x": 7.5}, "6,2"],
-      [
-        {"y": -0.875, "x": 2.5},
-        "0,2",
-        {"x": 1},
-        "0,4",
-        {"x": 5.5},
-        "6,1",
-        {"x": 1},
-        "6,3"
-      ],
-      [{"y": -0.875, "x": 5.5}, "0,5", {"x": 3.5}, "6,0"],
-      [
-        {"y": -0.875, "w": 1.5},
-        "0,0",
-        "0,1",
-        {"x": 11.5},
-        "6,4",
-        {"w": 1.5},
-        "6,5"
-      ],
-      [{"y": -0.375, "x": 3.5}, "1,3", {"x": 7.5}, "7,2"],
-      [
-        {"y": -0.875, "x": 2.5},
-        "1,2",
-        {"x": 1},
-        "1,4",
-        {"x": 5.5},
-        "7,1",
-        {"x": 1},
-        "7,3"
-      ],
-      [{"y": -0.875, "x": 5.5}, "1,5", {"x": 3.5}, "7,0"],
-      [
-        {"y": -0.875, "w": 1.5},
-        "1,0",
-        "1,1",
-        {"x": 11.5},
-        "7,4",
-        {"w": 1.5},
-        "7,5"
-      ],
-      [{"y": -0.375, "x": 3.5}, "2,3", {"x": 7.5}, "8,2"],
-      [
-        {"y": -0.875, "x": 2.5},
-        "2,2",
-        {"x": 1},
-        "2,4",
-        {"x": 5.5},
-        "8,1",
-        {"x": 1},
-        "8,3"
-      ],
-      [{"y": -0.875, "x": 5.5}, "2,5", {"x": 3.5}, "8,0"],
-      [
-        {"y": -0.875, "w": 1.5},
-        "2,0",
-        "2,1",
-        {"x": 11.5},
-        "8,4",
-        {"w": 1.5},
-        "8,5"
-      ],
-      [{"y": -0.375, "x": 3.5}, "3,3", {"x": 7.5}, "9,2"],
-      [
-        {"y": -0.875, "x": 2.5},
-        "3,2",
-        {"x": 1},
-        "3,4",
-        {"x": 5.5},
-        "9,1",
-        {"x": 1},
-        "9,3"
-      ],
-      [{"y": -0.875, "x": 5.5}, "3,5", {"x": 3.5}, "9,0"],
-      [
-        {"y": -0.875, "w": 1.5},
-        "3,0",
-        "3,1",
-        {"x": 11.5},
-        "9,4",
-        {"w": 1.5},
-        "9,5"
-      ],
-      [{"y": -0.375, "x": 3.5}, "4,3", {"x": 7.5}, "10,2"],
-      [{"y": -0.875, "x": 2.5}, "4,2", {"x": 9.5}, "10,3"],
-      [{"r": 30, "rx": 5, "ry": 4.5}, "4,4", "5,5", "5,3"],
-      [{"x": 1}, "5,4", "5,2"],
-      [{"r": -30, "rx": 11.5, "x": -3}, "11,2", "11,0", "10,1"],
-      [{"x": -3}, "11,3", "11,1"]
-    ]
-  }
-}