[schiffern]

That's not really relevant.

Charged particles from the Sun (SEPs) aren't what determine the design envelope for radiation shielding. Your overall dose will almost entirely come from galactic cosmic radiation (GCR) at much higher energy levels, which is significantly harder to shield against.

Those particles are what ultimately determine your shielding thickness requirements. That's true whether you're on Venus, or Mars, or a space colony.

[Retric]

https://ntrs.nasa.gov/api/citations/20205008318/downloads/20...

NASA’s direct comparisons between New Mexico (55) and Antarctica (160) only showing a relatively modest decrease from earths magnetic field when measured by high altitude balloons, but again very little GCR reaches the surface.

To be clear a very small fraction of GCR is extreme high energy particles which penetrate just fine.

[schiffern]

Hard to say, since that's in grays instead of sieverts. The two can give very different curves.

>again very little GCR reaches the surface

On Venus there would be less shielding than on the surface of the Earth.

The minimum acceptable altitude is ultimately limited by temperature, not pressure or radiation.