Thanks Glen,
My mind just told me that maybe the single tip (less chamber protrusion) might allow for a better burn. Also reading that the single tip doesn't last as long so I figured maybe it burns better and depletes quicker. Which is fine by me.
I did swap them out when I did valve clearances and nil effect was noticed. Car starts the same, consumption seems the same everything seems the same.
I reckon whichever one you find go for it. I'll probably go back to OEM (next time round) just for peace of mind.