> figuring out things like exactly where the minimum threshold sits for gravity

Now there exists some evidence about that threshold.

Experiments with mice on the ISS have shown that at least for them a third of the terrestrial gravity is necessary for avoiding severe health problems and two thirds of terrestrial gravity is the threshold necessary for avoiding all health problems.

That means that even the gravity at the surface of Mars is likely to be insufficient for avoiding all health problems.

This does not mean that travel through the Solar System or life on Mars or on the Moon are impossible, but it means that for any of these it is necessary to use rotation to provide artificial gravity for the spaces where humans will spend most of the time.

This will increase costs for spaceships or for surface bases, but technically it is a relatively easy problem to solve in comparison with the efficient recycling of all materials.