Jagrc,
I don't follow your reasoning; as Whistule pointed out, a part that dyes well but leaches badly when sealing is a sure sign of excessive pore size.
If you increase the acid concentration, you will make the pores even larger, unless you also increase the current density substantially. The dissolution rate (the anodize dissolving as it forms) wil also be very high with acid that strong.
It sounds to me, that you were not actually anodizing at 4.3 A/sq.ft. (120 mA for a 4 sq.in. part) but at a lower current density. How did you measure the current?
I know several people who use something like Tim's steam sealing method; he is right, it works fine.
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