Nice and definitive, M_D.
To answer Sid's cathode question:
The possible cathode issue you raise would be a connection problem, not cathode area actually. If CC isn't being compromised too much by the rack SA, CC will raise the voltage to compensate for what it sees as lower conductivity in the anodizing tank circuit. This is why cathode area isn't critical at all in CC anodizing circuit. Yes it is a circuit and all the physics and electronics math does apply.
As far as calculating the exact compensation required by the racking it is certainly possible, using Ohm's Law and Kirchoff's Law of DC Circuits. You will need to know the SA of the submerged portion of the rack, the SA of the work, the conductivity of the Ti alloy, the change in bulk resistance of the work as it anodizes, and the conductivity of the electrolyte. To do it accurately the math will be messy, and the applied ASF will have to increase somewhat over the anodization time, not remain at one value. I think a simplification can be made, where only a fixed increase in current density will work well enough. M_D is probably close to that right now, but his increase in ASF would only apply to his setup and his racking. You will need to develop a fudge factor that works in your case.
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