Well, things got backburnered for a while and now I'm ready to get back on top of this.

I'm looking at 4 different Autolite 606 spark plugs...

They have:

XP606 Iridium $6.49ea
ASP606 Copper $1.69 (are you guys suggesting these are fine?)
AP606 Platinum $2.79
APP606 Double Platinum $3.99

Thanks guys