As an alternative to storing entropy, store the mnemonic generated with the entropy. Steganography may be useful when storing the mnemonic. The random mnemonic generator on this website page uses a cryptographically safe random selection generator. The inbuilt random generator can usually be trusted a lot more than your own http://collinmmss433.lucialpiazzale.com/opening-the-power-of-bip39-a-comprehensive-check-out-word-lists-and-secure-pocketbooks