A blank cell must always follow an opening Nemeth Code indicator, and a blank cell must always precede a Nemeth Code terminator; these blank cells do not represent any space in print. The spaces in print are transcribed separately.
So, the appropriate transcriptions for your examples are:
where the opening parentheses are not followed by a print space, and the closing parentheses are not preceded by a print space.
Sometimes it helps me to think of the Nemeth switch indicators as three-cell symbols: