Column-staggered left half with thumb cluster

Same 36 keys, columns offset for finger length, spacebar broken into four
stepped thumb keys. Comes out ~7u wide instead of 8.5u because the function
row loses the 104's arbitrary gaps.

Also records the tenting dependency: hardware is CAD, but mounting holes are
PCB and need a case scheme chosen before routing.

Co-Authored-By: Claude Opus 5 <[email protected]>

README.md

@@ -160,6 +160,47 @@ socket footprints per key with one populated.
 
 See `docs/half-left.svg` and `docs/half-right.svg`.
 
+### Column stagger, not row stagger
+
+A 104's row offsets are a typewriter artifact — mechanical linkages needed the
+room, hands didn't. Since these are new PCBs, the columns get offset vertically
+to match finger length instead: middle column highest, pinky and inner-reach
+columns down ~0.4u.
+
+`docs/half-left-staggered.svg` is the left half rebuilt this way. **Same 36
+keys**, and it resolves into a clean 7-column grid:
+
+| Column | Holds |
+|---|---|
+| 0 (outer) | Esc, `, Tab, Caps, Shift |
+| 1–5 | the finger columns, 5 keys each |
+| 6 (inner reach) | F6, 6 — only two keys |
+
+That last column is honest rather than a defect: on a 104, `6` and `F6` really
+are an index-finger stretch, and the stagger makes it visible.
+
+Side effect worth having: it comes out **~7u wide instead of 8.5u** (~134 mm vs
+~162 mm), because the function row no longer carries the 104's arbitrary gaps.
+Narrower *and* better.
+
+### Thumb clusters
+
+Both spacebars break into stepped thumb keys. On the left that's Ctrl / Win /
+Alt / Space stepping down and inward. This is where the pinky relief actually
+comes from — a stock 104 puts Tab, Caps, Shift *and* Ctrl on the weakest finger.
+
+⚠️ Only about **two or three** of the four are genuinely comfortable; the
+outermost is at the edge of thumb travel. Consider dropping Ctrl to a home-row
+mod and reclaiming that slot for a layer key.
+
+### Tenting
+
+Tenting hardware is a CAD/case job and comes after the PCB — but the **mounting
+holes are PCB**, and where they go depends on the case scheme. Decide sandwich
+vs tray *before routing*, or you'll find the case wants a standoff exactly where
+a switch or a matrix trace already is. Holes can't be added later without a
+respin.
+
 ### RGB: numpad underglow only
 
 Per-key RGB is arithmetically impossible on a bus-powered hub. Each half sits on