Under your conditions of 1 sq.ft. max surface area; and 6 A/sq.ft. max current density, and also assuming PAR = 2.5 Ohms/sq,ft.,
you will need:
V = I x R, V = 6A/ sq.ft. x 2.5 ohms/sq.ft. = 15 Volts.
This doesn't allow for any voltage loss due to less than ideal electrical connections. So add say 15% for this:
15V x 1.15 = 17.25 Volts.
If you were tightly bolting the anode connection to the work with aluminum hardware, like I did in my paper, you would not really need to add this 15% to the required voltage. If on the other hand, you were just hanging the work from aluminum or titanium hooks, as shown in the instructions, the connection resistance could be quite high, requiring much more voltage to overcome. doubling the voltage requirement to 30 volts would not be unreasonable.
Let's assume you will tightly bolt the connection, so you only need 15 Volts. Now for the required current :
6 A/sq.ft. current density x 1 sq.ft. area = 6 Amps anodizing current.
So you need to have your VCCS be capable of 0 to 15 Volts, and 0 to 6A minimum.
If you go to the online manual on the caswellplating.com site, at the bottom of the page, click on the title "Building a Power Supply". The circuit described by Don Foreman is a VCCS. I would replace the Darlington power transistors he used (TIP 120) with power MOSFETs, which are now cheaper than Darlingtons, easier to design circuits with, and are easier to get these days. For 6 Amps, you would only need one power MOSFET, two if your heatsinking wasn't that good. Start there.
Next question; your 12 V transformers, what is their output current rating (in Amps) or their VA (Volt x Amp) rating?
Next question; your rectifiers, are they diode bridges (4 diodes in one package) or full wave rectifiers (2 diodes in one package) ?
Next question; what is the voltage and capacitance (microfarads) ratings of the big capacitors you have?
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