Ah I should have made a bit more detailed message explaining the road I wen through already I guess :-)
I know that RAG gets recommended more for adding information. It is the fastest way to retrieve information. However it allows only a shallow understanding of it and the LLM will have problem using information from several different files to give you. You can't, for example, give it 1000 emails and ask to list the problems encountered in project A and how they were solved.
Fine tuning can add facts. This person added the documentation for Unreal Engine 5 in Llama 7B. Or this company added financial knowledge to Llama 13B. These are my inspiration. When using LORA it requires higher ranks and crucially to do the fine-tuning on a foundation model and only after your own fine-tuning, do the instruction fine-tune.
I am wondering if there is a way to make the last step easier by reapplying the same LORA.
I guess I am also wondering why we can't directly fine-tune facts into an instruction-tuned model. I tried, it does tend to remember the way to interact with instruct prompts but the format is a bit corrupted by the new dataset. I find it a bit weird the speed at which such models forget past things as they are fed new tokens.