I have a stock distributor, coil and resistor wire but an Ignitor I module. I use a general purpose relay I bought at Auto Zone. It's mounted up front by the voltage regulator, and driven by the wire that used to go to the + terminal on the coil. It gets 12 volts from the BAT terminal of the voltage regulator. This works fine for me and the original wire to the coil seemed like the logical one to drive the relay.
On the wiper motor wire, does it get power when the wipers aren't on? Even if it does, I bet that it does not get power when the key is in the start position. Most all accessories don't get power in start, to give as much power as possible to the starter motor and ignition.
Pat