I run NGK 8's or 9's with gas or alcohol, if i'm running the V-gaps i set them at .022, gas or alcohol, if i'm running the ES version (flat tip) i set them at .025. All use MSD ignition. In my opinion .045 is way out of range. I know that the old HEI setups GM called for .040/.045, but with multi-spark-discharge aka MSD you'll get much better firing of fuel charge setting them at less than .030.
JMO
Zip.