reaction control - Limit the production of hydrogen in a small container

I have to produce hydrogen at a near-constant pressure inside of a really small container without using an automatic pressure release value. I would like the pressure to be relatively high, but the most important aspect is that the exact pressure needs to be predictable. I was thinking of utilizing the reaction between aluminum, water, and sodium hydroxide.

Al2O3 + 2 NaOH + 3 H2O  → 2 NaAl(OH)4
Al2O3 + 2 NaOH          → 2Na+ + 2[Al(OH)4]-

2 Al + 2 NaOH + 6 H2O   → 2Na+ + 2[Al(OH)4]- + 3 H2
2Al + 2NaOH + 2H2O      → 2NaAlO2 + 3H2.

Now, I know the pressure will slow down the reactions, but will the reactions completely stop at a certain pressure? If so, how can I deduce that specific pressure given the different concentrations of reactants and constraints of the container?

Safety is my number one priority, so I need to make sure that I can predict this pressure to a high degree of accuracy. If the pressure is too high, I won't even attempt anything. Any advice on this would be greatly appreciated.