How do you ensure a role is part time?

[Orangeis]

I've applied for a job that due to a mix up was advertised as PT but is actually FT. The hiring manager really likes my skills, but doesn't want a part timer.
She's extended the deadline, done a round of interviews, pretty much done all she can to find a full timer.
My skill set is fairly unique so I think she's struggled, and has now invited me to interview. If I'm successful I'm not sure the questions to ask to ensure the role is a part time workload. Obviously I've not done the role so wouldn't understand "We've removed the auditing function and given it to someone else" for example, what does that look like. So, what questions do I need to ask to ensure the work fits the hours? I'm not desperate to move, so I'm not going to accept at any cost, but I would be keen if the workload was manageable.

I’d approach this interview as an absolutely two way street. They have a full-time job of tricky, specialised work that needs doing. You are a competent and wise professional who has the skills but not the availability. How can you help them? Basically, treat it like you are a consultant solving their problem. As you know the manager “doesn’t want a part timer” that’s a massive red flag! You will need to find a way of framing it that keeps out of that “part timer” dynamic- and as it sounds like they need you more than you need them, there may be options. They can’t have you full time! Could you work with a junior who you are training up, for instance?

@DustyDoorframes thank you, what a valuable perspective! Would you discuss this at interview stage or wait until offered the role?
I don't think she's anti PT on principle, 2 people used to job share the role, but she recognises it'll be very hard to find two competent people at this stage. I could indeed suggest using the other portion of the FT salary to get a junior who would be cheaper, we could provide more than 5 days cover between us so it could be a win win.

Either at interview or even before, maybe. It sounds like you are not desperate for the job, so making sure it will work for you in an interesting and useful way seems like the priority?