People change there sensitivity higher all the time (and get more noise ) but they don't change there noise cancel channel for the type of coin they want to find because the ctx knows best they will say but sensitivity and noise cancel or very conservative settings and you have leeway . To much sensitivity and the #s are all over the place same can be said with a channel to far from the recommened channel . If I get 6 for noise cancel I can go to 2 or 3 if I get 8 I can go to 11 this is with the stock coil the 6 has a bigger range before emi enters the picture .
I let the detector tell me what to hunt for if I get 8 or 9 I will go to 11 if I get 6 or 5 I will go to 2 or 3 and hunt high conductors not saying 6 won't give you silver or nickels .
Lower freqs give a better sound on high conductors just as higher freqs give a better signal on low conductors. But if you want the best settings your going to have to use plants a clad dime and nickel buried at 7 inches where you hunt I have plants at all my hunting spots . I get my settings from these before I hunt other wise your just guessing ground and emi change daily so why guess .sube