To avoid leaks from stove after disconnecting the bottle, you could buy a self clearing stove like Primus Omnifuel or Optimus Polaris, etc. These stoves have ON and OFF marks on the bottle position needed to draw fuel (ON) or air (OFF) from the bottle. To clear the fuel line just reverse the bottle to off, 1-2 minutes before you need the flame to stop. All remaining fuel from the line will be consumed, the remaining pressure in the bottle helping with that. This requires some anticipation of course. Not sure if this trick can be used with a MSR bottle and pump, as I never had a MSR stove.
From the excellent blog Adventures in Stoving:
To turn the stove off, one again rotates the fuel tank around the axis
formed by the valve into the "OFF" position. In the "OFF" position,
the dip tube, which would normally be in the lowest portion of the
tank, submerged in fuel, now points upward and just draws air. This
air now flows out through the valve, clearing the fuel line and
depressurizing the fuel tank.
When buying O-Rings for the fuel bottle, be sure they are the most flexible type which resists to hydrocarbons and oils, that is Nitrile rubber. The type to avoid is Viton, since this will become more inflexible to cold.
Nitrile vs Viton rubber:
Viton® seals are prone to failure below -15°C in dynamic applications,
as they become inflexible and hard.
But remember to change them often, I would say once a year, as Nitrile is more easily degraded by ozone :
Nitrile vs Viton® is not resistant to degradation from weather and
ozone exposure. Designed to resist most oils and lubricants, more
importantly petroleum based lubricants, these seals have other
benefits, such as superior abrasion and tear resistance, making them
suitable for heavy duty industrial applications.