I am a sole proprietor. Do I register as an individual or as a firm?

As an individual. A sole proprietor applies as an independent research analyst, and you personally must satisfy the eligibility conditions that apply to an individual.

That determines a good deal downstream. You pay the individual fee slab of ₹2,000 application and ₹3,000 registration, rather than the body-corporate slab.

You are not required to appoint a compliance officer, because that duty falls only on non-individual analysts and research entities.

You may not provide distribution services at all, which is a restriction specific to individual analysts.

If your only business is research, you are an independent research analyst. If you do something else as well, look at the part-time category.