Haven't chuckled at a thread like this in a while. Cashin, it would be wise to listen to the YEARS of experience of CC members. But I love your bravado man, and there is SOME credence to the theory that if the 1/2 games are weak and easy to win during local poker room trips (like mine!) that you can compete competently at online games of .50/1 or even 1/2.
The problem is bankroll management ... when you go to the casino you'll take 100 or 200 or more with you, right? But you can always get more money from the ATM, or come back when you get paid. So your "actual live poker bankroll" is some unknown number that you can guess.
No matter who you are, or how good you are, you will have downswings. It happens to the top pros, and the online pros, and superplayers here on CC. How do we know? We track all their damn stats and analyze them! It happens, so prepare for it.
Now the question as to "how many buyins?" , you can find MANY threads on that topic. It matters how many tables you play at once too. But if you continue to see your BR go up and up you are definitely playing at the right level.