RE: Temp gun
The best temp gun is right there with you SPIT right on the engine head if it evaporates in a few seconds your good just sits there lean it up a hair theres more power to be had and if it dances off the engine richen it up a quarter turn, but if you are really worried about it IR temp guns can read way off depending on sunshine wind blowing and the surface itself(anodized or polished) If you want the closest reading possible get a mip on-board temp gauge and position the sensor on the lowest fin of the cooling head 180degrees opposite of the exhaust.