Of course you can use an array. They are no different then separate variables but more useful.
And “converting something to hex” does not exist. A variable is a variable, only difference is the way we represent it. Think about is as languages, with one, 1, één, uno, ein, un we alle mean the same thing only in another representation. Same goes for a varaible only we are really used to decimal. But no matter we represent it in decimal, hexadecimal, octal or binary, it’s still the same value. We only need to tell the compiler which it is when we enter it.
197 = 0xC5 (hex, 0x is to tell it’s hex) = 0305 (octal, leading 0 tells it’s octal) = 0b11000101 (0b for binary)
After we assigned it to a variable we can choose how to represent it:
Serial.print(var); //or Serial.print(var, DEC) normal decimal
Serial.print(var, OCT); //octal
Serial.print(var, HEX); //hex
Serial.print(var, BIN); //binary
And can we do stuff like:
var = (0x0F << 4) && (0b10101010 || 0100);
Not very clear but very valid