you will be surprised how good a "simple" base turns out. the CRO development base started with oil, onion, garlic, ginger, tom puree, salt, curry powder, water.
i've tried quite a few derivatives since then for example changing the curry powder to turmeric and paprika and then to coriander and turmeric.
it's a real interesting approach to take and u'll lean loads by stripping it back.
trouble for me was that whilst i still stick to the "simple" base as best i do feel certain additions make positive changes for example carrot. it's all down to personal preference of course and will look forward to your findings particularly given the chef's input as your starting point.