We had a fire last year and had to remove our plaster ceilings. We’re left with beams that have all kinds of shims etc. that were used to level the lath. Every drywaller has had a different idea of how ceiling should be prepped. A few have said they didn’t want the job.

None of the joists are structural. I just checked the floor/ceiling above and it is pretty level and flat. 

The floor of the room is definitely not level so measuring up from the floor (one suggestion) wouldn’t work. The beams are definitely not level as they are all different sizes and have been affected by settling. We are installing floor to (almost ceiling) pantry cabinets on one wall. 

Would it be easier to just remove the old joists (we would reuse them wood for a furniture project) and add new ones - measuring down from ceiling/upstairs floor to the lowest point of the beams? 

The picture with door shows the one beam that has 2.25 change in level. 
Thanks for your input. 

![enter image description here](https://i.stack.imgur.com/hCl0H.jpg)![enter image description here](https://i.stack.imgur.com/K3jbE.jpg)