cooler spark plug

[old skool]

I am running W16Y Champion Sparkplugs in my car right now. I was reading Jim's "My Four Banger and Me" book (Good book by the way and very informative). He recommends a cooler plug for a High compression head. What would be one step down from W16Y? I found some W14 Champions. Would those work? They don't have to be champions. Some of the charts I am looking at online are hard to follow. Open to any recommendations.

Thanks,
Marty