Inverted Canister stove efficiency vs Climbers canister stove efficiency

I'm aware of two techniques for using canister stoves in sub-freezing weather. The first is to invert the canister by separating the stove from the fuel thus creating a liquid feed. These seems popular around here.

The second and seemingly older method is to use copper tubing to use a small amount of heat from the stoves burner to warm the canister, thus increasing the canister's pressure to normal levels. This method, I realize is slightly more complicated that I'm explaining and I know that many consider it dangerous.

However, setting aside the fact that it may be dangerous are they equal in efficiency? If not, is the amount significant?

I'd be curious as to how much fuel people find themselves consuming using canister stoves + these two methods to melt snow.