[sage]

Boy, that was a really good exchange of information. Thanks to all.
I think we all might have been saying the same thing but envisioning the process differently in our minds eye. It's nice to see - for me, that I'm not thinking alone.
Cameraman - It's too bad you didn't dye the parts in your experiment all at the same time, and the same color. This would also have answered a few questions and added some more proof to the theory since the dye and the shade achieved would have been a pretty good gauge to the anodized layer of each part. I was planning to perform exactly this experiment and haven't gotten around to it yet. If you have occasion to repeat it as described I'd really like to know how it turns out.
i.e different sized parts, anodized together, and dyed together.

Good work none the less.
The reason I suspected that the surface finish and other parameters have a lot to do with the current is as follows:
I anodized two identical parts, polished exactly the same. For reasons I won't go into one of the parts surface got messed up but they were identical when they came out of the dye. I decided to strip the one part and try to re-do it with exactly the same A/sqftas the first and try to dye it the same too. I couldn't get them to match, becausue my process isn't really too well controlled. I decided the only way I was going to get them the same was to strip them both (one for the second time) and re-do them. Upon stripping the piece that was being stripped for a second time looked different (very dark) in the stripper. After stripping them I polished them both again. They looked identical after polishing so I lost track of which was which. During anodizing one of the parts created bubbles alarmingly more than the other but eventually they settled in to be the same. When I went to dye them I lost track of them again but one of them took the dye very quickly to the shade I required. The second took about 3x the time to get to the same shade. Luckily I got them to match (good enough). The moral of the story is maybe that stripping messed up the alloy or the surface on a microscopic level or something.
What a crazy process. So many variables. How do we ever manage all of them.

Sage