an 8-sided or 4-sided dice would convert better into a binary number than a 6 sided one since they are power of 2.
In which way, other than speed, is it going to better to use an 8-sided dice over a 6-sided one? Yes, 8 is 2
3, and can return all binary values between 000 and 111. In 6-sided dice, you have [0, 1, 00, 01, 10, 11]. An alternative way to generate entropy, is to not use the sum of the outputs as the seed, but write down the dice results (1, 2..., 6) and SHA256 the output. That way, you can have a fixed number of dice rolls.