Yeah, I agree with Roger. I doubt that the contact is all that effective. Though I am sure it accounts for *some* heat transfer. The very thin line described by the sharp fold would not have enough surface area to transfer any significant quantity of heat.
For short burns, a relativly tight fitting wind screen would do well with trapping heat next to the sides of the pot. Hanging down over the edge of the pot, typically a larger heat loss area due to mixing with cooler air/turbulence, the folded screen would channel hotter air up into the windscrren where it could do usefull work, heating the pot sides.
Of course, you have to be carfull you don't overheat the canister with "toppers. Such stoves were never really designed for such use. (Not that that ever stopped any of us.)
Again, I agree with Roger that a remote stove is best for using tight fitting windscreens. The popular Caldera Cone is, perhaps, not the best design for the wind screen, however. The tapered design, while quite stable, allows edge turbulence right where you want to eliminate it. The thermal feedback is highly amplified in such a screen, though. Heating the stove entirely. This can be mitigated by allowing air intakes at the critical parts, the fuel tube connection(unless lenghened,) the valve and seat which can distort inder a couple hundred degree's of heat, and the removal of any plastic parts, obviosly.