There are plenty of ways you could do this, or something like it.
- Take your two pieces of entropy and simply concatenate them.
- Add them together.
- XOR them together.
- Combine them in a hash function.
- Use one as a seed phrase and the other as a passphrase.
I can have this site generate a random one of 15 words. (Obviously after cloning it from GitHub and moving it into offline computer.) Then presumably I could simply go into "Show entropy details" and add my dice rolls to the entropy until I get up to e.g. 24 words. Anyone here welcome to critique this idea.
When you click "Show entropy details", it will display the generated entropy in hex. You would either need to roll a 16 sided dice, convert your standard 6 sided dice rolls in to a hex string, or my preferred option would be take the raw binary and add your dice rolls to that, with 2/4/6 being 0 and 1/3/5 being 1.