Happy to help! I have a library implemented you can use as an example. May be this can answer some of your questions already.
nostr:npub1efz8l77esdtpw6l359sjvakm7azvyv6mkuxphjdk3vfzkgxkatrqlpf9s4 I'm working on a full integration of NIP-19 in nostr:npub1phpdev2d38u5hzs4jrsh360mevh0rjctu9669quy97wu23u8sqdqpfha0j but as regular webdeveloper I'm struggling to write the correct low-level stuff with the encoding/decoding with the bits and bytes before all is being encoded with the bech32 helper.
Work in progress: https://github.com/nostrver-se/nostr-php/tree/nip19 and this is the writeTLVEntry() method where I'm taking care of this: https://github.com/nostrver-se/nostr-php/blob/nip19/src/Nip19/Nip19Helper.php#L200.
So I'm looking for some help / guidance 🤓 Can you help me along? 🙏
Discussion
I already checked it, but handling the TLV data is not there so to me it seems incomplete if you check the NIP. But thats why we could collab on this to also include it in that package 😃