A LONG-SHORT, SINGLE-INSTRUMENT, 4-HOUR mean-reversion strategy on ETHUSD.HYPERLIQUID that fades stretched dislocations on both sides (buy stretched-below-mean, short stretched-above-mean) and exits on reversion toward a 4H VWAP/EMA. This is the directly analyst-recommended next move, grounded in three fresh facts: (1) the HL BTC daily TS-momentum LS just PROMOTED (Sharpe 0.68) — the BTC momentum edge is captured at daily cadence, so do NOT re-express BTC momentum at other cadences; (2) the 4H probe proved HL 4H has GENUINE DEPTH (~1.3yr from 2024-01, 178 trades) — it is NOT the ~2-month sub-hourly wall and is MORE validatable than daily (178 vs ~30 trades), with a 15-day holdout spanning ~90 4H bars (vs ~15 daily); (3) the analyst's explicit guidance: pursue 4H on a DIFFERENT mechanism/instrument — e.g. ETH mean-reversion at 4H. This hypothesis is exactly that. Why it is the strongest available slot: 4H is the ONLY HL sub-daily cadence with CONFIRMED adequate depth (15-min is data-walled at ~2mo and banned; daily is holdout-sparse; 1H depth is still unverified — the pending 1H ETH probe is riskier). It uses the clean-sizing ETH instrument (64.5%; over-exposure localized to BINANCE + HL SOL early data), mechanism-matched to ETH's CHOP (ETH lacked momentum/breakout edge, which is exactly the regime mean-reversion exploits), and the mechanism is DISTINCT from the promoted BTC-momentum sibling (adds genuine diversification, not a clone). It fills the dominant direction gap (long_only 85.9% vs <=55%) and the under-weight HL venue (7.3% vs >=20%). CRITICAL GEOMETRY FIX (carried from what just worked): every prior VWAP-reversion run failed on INVERTED payoff geometry (avg_win < avg_loss); this uses an EXPLICIT geometry gate — only enter when distance(price, mean target) >= geom_mult x stop_distance (geom_mult > 1), net of the ~0.09% HL round-trip — so avg_win > avg_loss BY CONSTRUCTION (the same wide-target/tight-stop discipline that gave the 4H BTC momentum run avg_win 5,077 > avg_loss 2,365). Bug-avoiding: pure OHLCV, fixed-fractional size, NO dynamic resizing, leverage 1.0, dual flat guard, flip-via-flat. REGIME GATE blocks fading genuine trends (no dip-buy in strong downtrend, no rip-fade in strong uptrend). PRE-REGISTERED ACCEPTANCE: (1) GEOMETRY — realized avg_win > avg_loss must hold, else the gate failed -> abandon. (2) SIZING — avg_position_pct should track ~95-100%; mild benign winning-leg notional drift (the 4H BTC run's 120.9% with plausible single-period returns) is acceptable, but a >~150% reading with impossible single-period returns means escalate. Data depth is already CONFIRMED for 4H, so no data-wall kill-switch needed (unlike sub-hourly). Low parameter count (mean lookback, stretch threshold, geom_mult, regime EMA, ATR stop, time stop).