Well I'm fairly new to the Nitro scene, and I've heard it's not the best to switch fuels, but I did and it hasn't done anything to my motor, it runs stronger now then ever.

Are those dents in the top of your piston??? Well the motor was definitely at over 280F to make the piston that dark, it doesn't look horrible but it should be a nice light/golden brown.. A good visual indicator is if you suspect your motor is running hot if it stalls or you shut it off if you can hear fuel bubbling inside the motor, or the heat sink is smoking or making noises like it's cooling down, those are sometimes indicators it's running too hot, also there's the spit test, if it bubbles it's too hot, etc..

As for the HSN, it's really hard to say, I like to tune by temperature. How does it idle, smooth? When you do a full throttle run and then let it idle how long does it stay at higher RPMs before dropping down to normal idle RPMs? I have my LSN tuned so after a full throttle run it stays at higher RPMs then idle for about 5-7 seconds, then it'll drop down to idle RPMs.

[8D]