In effect the particle A should have no relative gravitational effect, B should have a positive effect in the upwards direction and C should have a positive effect in the down wards direction.

A balloon of helium has the potential to lift the amount of weight that is equal to the difference in mass of the volume of Helium and the mass of air that is displaced. There is therefore an upward force provided by each molecule that is equal to it's buoyancy or mass difference times the gravitational constant.

To explain this better 24 litres of helium would displace 24 litres of Air so the mass of the 24 litres would be 4gramms rather than 29gramms. There is therefore the potential to lift 25 grams so the overall force upwards is 0.025 x 9.8 N. mathematically this equates to (Mb-Ma/1000)*9.8 (negative = upwards, positive = downwards)

In the case of an individual molecule it would be (Mb-Ma)x1.66054 x 10E-27 X 9.8 N. again this would be negative for upwards and positive for downwards.

We can easily expand the area so that there is more space between the molecules if that helps the reality of the gas.

In a big enough system the gasses should separate out completely given enough time with only a small overlap in the "mixing region".

If I can get it to give the results I need with a reasonable level of scientifically sound assumptions then I'd like to use it in a lecture and a scientific paper. (Naturally you will be acknowledged.)

Sorry if it seems a bit confused above.

C