ならともかく・ならまだしも: the difference
ならともかくN2
Meaning
If it's
Past papers
Tested 3 times in past papers
Example
生魚ならともかく、納豆は食べられません。
If it's raw fish, sure, but I can't eat natto.
ならまだしもN1
Meaning
A is fine...but B is not, If it's ~ then it is ok...but ~ is not, It's different when...but, It's not so bad when...but
Past papers
Tested once in past papers
Example
すみませんが、付き合うぐらいならまだしも、結婚は無理な注文です。
I'm sorry, dating is one thing, but marriage is out of the question.
How to tell them apart
「ならまだいい」 is casual: 'that would be a bit better'.
「ならともかく」 is 'never mind A; the real problem is B'.
「ならまだしも」 has the sharpest contrast and the strongest emotion: A I could let go, B I cannot.