I am assumming that you want to increase dwell. So do the math and put a resistor on the brittle wire. You will get less secondary voltage but maybe you can compensate for that...or so they tell me

"The dwell period on an engine with electronic ignition is controlled by the current limiting circuit within the amplifier or Electronic Control Module (ECM). The dwell on a variable dwell or constant energy system will be seen to expand as the engine speed increases, compensating for the shorter time period.

The term æconstant energyÆ refers to the available voltage produced by the coil. This, regardless of engine speed, will remain constant as opposed to contact ignition where an increase in engine speed means the contacts are closed for a shorter time period. The coils saturation time can be seen on Fig 1.4, where the time available to saturate the coil is a constant 3.0 milliseconds regardless of the engine speed. The saturation time is considerably lower than that of a contact system due to the coils supply voltage being approximately double that of a ballasted contact system and the coils primary resistance approximately halved. This will result in a far higher current, saturating the coil with amperage that would not be possible on a contact system."