Anyone know the heat range of Ninja plugs? I'm assuming 5, 6, 7. Hottest to coldest. I feel I need a hotter plug and I got a couple of 5's, was running 6,but they didn't change my tune much at all, and eyeballing them the 5's look virtually identical to the 6's to me.

FWIW, I'm running right at 5000ft alt. w/30% nitro. To get it up on the pipe it seems like I'm having to run on the lean side.