Right now I have no idea whom to hire, possible costs etc. I've been contacting a few firms I found online, also here, and the best I got was a polite reply saying they are no longer in business (worst: no reply).
So I've been considering to focus myself mostly on the description of the invention with possible claims in mind, and try to come up with claims to the best of my abilities then submit and start looking for professional help.
As far as I understand, claims can be changed, so as long as the description of the invention is sufficiently clear and novel, there should be sufficient space for a professional to find the right formulation later on?