So, the fastest way to create a safe bitcoin private key with the physical 256 coin flips is appox. 15-20 minutes.
since your tool supports it, try finding a 16 sided dice and roll that. these dies are also a popular way of creating random numbers (in hexadecimal format) and they are specially designed to be unbiased and produce a truly random result. the befit of it is that you only need to roll it 64 times which is a lot less than 256 times flipping a coin.
Cool idea! You are right, my tool allows to input the HEX value of the private key.
I searched 16side HEX dices and found a lot of them in internet for 1-3USD. Will order this dice for my experiments, nice thing.
Thank you!