Actually, there's one other possibility: 3.0 point without gorget is 1290 rather than 1293. 1290 * 1.05 = 1354, which is the max observed damage, so 1290 is within valid range.
1290 would have a 1.0 of 430
Increasing to 462 with 200/1024 fTP
158.77 - 168.90
base fTP: 2.56 - 2.70
Increasing to 463 with 200/1024 fTP
163.90 - 174.02
base fTP: 2.48 - 2.62
So an fTP in the 2.5 to 2.7 range, but requiring a higher Chr WSC mod.
Picking one at random: Supposing 2.5 fTP, which would mean a base damage of 172. That requires 48 WSC, which is ~72% Chr mod.
Supposing a 60% Chr mod: That's 40 WSC, total base damage of 164, and a 2.625 fTP (clean fTP value). Note: that generates 430 base damage for no gorget, and 462 base damage with gorget; both fit observed values.
Doing more testing on the WSC first.