I think Tony's approach, using Soldermask over complete Gold is brilliant, and I wonder if it is more costly...it could be argued that it is less expensive.
Given the very high cost per unit of metal deposited, never mind the control issues, for both Electroless Nickel, and Immersion Gold, the cost of the extra gold used probably gets lost. (Did I mention absence of catalyst in Tony's process?)
Hats off to you Tony, GREAT IDEA.
Rudy Sedlak