WFC design session v27: reasoning

This sweep was supposed to hunt the Td sweet spot from below the 1A ceiling by trading cold-pure Q for warmer, slightly-more-conductive water. It did not get me there, and I want to be honest about why. Every top candidate lands at ~3700-3940 Td — five to ten times above the 80-250 Td cold-chemistry window I'm scoring for. The scorer is rewarding these on resonance quality and displacement fraction (98.9%), not on landing in the CGDE regime, so the 0.651 plateau is a local trap, not a win.

The deeper problem is exposed in the numbers: tank Q ~82 magnifies 120V to ~9.9kV, but that same Q circulates 79.8A in the tank and forces 7976mA average input at 10% duty. That blows the <1A ceiling by 8×. Warming the water and nudging ppm lowered nothing meaningful — C_dl scaled with surface treatment (4.4→17.5µF) but cell series R stayed pinned at 1.3Ω and the field across the 0.1mm film stayed brutal because cell voltage never came down.

I'm provisionally adopting #4 (6mm/7.6mm × 90mm, ×6 breakdown margin) — not because it's good, but because its ×6 dielectric margin and lower per-molecule field (3.16 mV) give me the most headroom to keep cutting voltage without arcing.

Next session I attack Q directly: drop tank Q toward 15-25 by adding deliberate series resistance or lower-Q chokes, accept a lower cell voltage (target ~2-3kV to pull the film into 250 Td), and re-sweep duty down to 2-3% to drag average current under 1A. Voltage is the wrong lever — Q reduction is the lever.