loch in scottish is pronounced like the jota (j) in reloj (watch) in Spanish, and I'm sure you know how does that sound, yes something like Jamon.
And talking about if it's correct to pronounce it like "k" or "ck", then I will simply tell you, it will be the same thing if you pronounce "reloj" as "relock" a Spanish person may recognize the word you're saying or may not, so if you pronounce the "kh" like "k" or "ck" then you will have to depend on the other person to be able to understand you or not, if you tell me in Spanish "ckamon" or "kamon" it will be hard for me to think that you mean "Jamon" so the "kh" is hard to pronounce but I think it's vital for a better understanding of the word pronounced, besides for you since you're brazilian it wouldn't be as hard
