Your basic approach is faulty.

The gelatin swells and allows the chemicals to diffuse in and out more freely thus making fixing and washing more rapid.

In acidic conditions, the gelatin is indeed less swollen, but the diffusion rate of chemicals is thus slower by a large factor.

And, BTW, this is why Ammonium fixers are faster than Sodium fixers. The Ammonium complexes of AgX are much smalller and diffuse out more rapidlly. Alkaline Ammonium fixers are thus very very rapid.

Another approach is to make an acid fix with a swelling agent.