If I was to say "I'll give you $50 for certain, or we can flip a coin: Heads I give you $100, tails you get nothing" what would be your answer?

If the answer is "$50 for certain" you are not ready for $50NL.

If the answer is the flip, you should be playing higher than $50NL

If you're not bothered, $50NL is right for you.

Mathematical reasoning behind this is in my BR management post in the digest.