So if they want to pay, how much should I say, to come off as professional to these people, more likely?
Being (or appearing to be) professional is not about how much you charge but about having the knowledge and experience to know how much you need to charge to fulfil the director's/producer's expectations.
It turns out that it's not scripted, so I have to boom for non-scripted people, while possibly operating the field recorder at the same time. I am just going into it now, and will find out exactly what I have to do, but the plans keep constantly changing, and re-assigning.
How on earth can you quote for a job without knowing if it's scripted or not? How on earth does a producer expect to hire someone without telling them what the job entails? How can your job/s keep changing and being re-assigned if you have a contract or written agreement?
I didn't know it was a documentary, as the add said feature film so I assumed they meant a scripted film with a somewhat controlled sound environment, rather than shooting in a loud public place. I guess I should have asked if it was a documentary before.
So in your OP you essentially asked how much you should charge for doing a job without knowing exactly what that job was or what the producer's expectation were? (see my previous two answers!)
I know from a couple of past projects over the last year, that it seems that most producers may tend to expect a person to do both jobs.
So, what have you learned about these types of producers from your past experience? For example, have you learned that these producers are working with scripts which are carefully crafted to allow 1 person to do both jobs well or have you learned that these producers are just ignorant of production sound and have unrealistic expectations? If it's the latter, how do you intend to comply with my first answer?
So far the production is run very poorly, with a lot of desperation and shortcomings on set.
From what you've described, isn't this scenario exactly what you should have expected?
In fact, I don't think I will be able to do anything to hurt this production since it's already so chaotic.
What makes you think that? Poor location sound will always hurt any production, regardless of how good or bad the rest of the production is. Furthermore, the producer already appears to have little or no idea of what is required to achieve decent location sound and almost certainly has unrealistic expectations. Therefore, if/when the location sound is poor, the chances are that the producer will blame you personally for it.
I want to get on a set to get filmmaking experience ...
Just out of curiosity, why do you want to get experience of a very poorly run set?
G