Try experimenting with opening the teeth and/or bringing the jaw out a bit. You will need to be more open for loud. A low C at FF is different than a low C at pp. Hope that helps. If that doesn't work, your tongue may be in the way (too high).
Think about creating a business plan and there are doubts that I will be able to create it myself. Is it worth contacting some third-party office
, to develop a business plan for me or it is better to try to create it myself? I would like to get feedback from people who have tried both the first option and the second.