I use a pair of MSD 6A amps on both my leading plugs (1 pair of leading plugs fire together and a pair of trailing ones fire separately) with Magnecor Wires. I have run at a fuel ratio of 10.0/1 (maybe richer ! , my wb only goes down to 10:1 ) and a big 0.9mm jet at 75% + (duty cycle of the HSV) WITHOUT any tipe of break up . When you introduce water into the combustion chamber you need a stronger spark , because of higher in cylinder pressures , additional conductivity caused by the presence of water and cooler temps , with an ignition amp. you can even use colder plugs without the associated problems
