The only thing I claim is safe is: 1) its done offline, 2) its done randomly, and 3) no one can know the method of creation. I will stick by that maxim. < this is the essence of the thread
I don't see the need for (3). Indeed, if (3) is at all useful to your security then I'd claim that you're not introducing enough entropy at step (2) and are being forced to rely on the extra entropy of your method being one among many plausible alternatives.
Certainly, 256 coin flips provides sufficient entropy. I believe 128 coin-flips is enough for critical cold storage even with the method known but I'm not a cryptographer.
While this is true, (3) may be important in case (2) is not perfectly knowable.
If I know
all of the circumstances surrounding your coin flips (from even a little bit, up to even the extreme of covert surveillance of your flipping), then (3) would have been helpful to you. The less others know of your method, the more of your secrets are secret.
Maybe you have your phone with you, and I can turn your phone't mic or camera on via remote. Maybe I can hear whether you are writing an H or a T or a 1 or 0 by the noise you make while doing it? The more I know of your process, the worse it is for you.