I have a bathroom wall that we are currently renovating in a 60s built house and the budget has been eaten up quicker than expected… (but about as quick as should have been expected maybe).

We need to tackle most of the plastering ourselves. One wall which we removed the tiles from looks like the material in the right of this picture .

I have 3 questions and am grateful for feedback to any of these if you can help.

1. has anyone any experience with plastering on this stuff? If so, am I on the right path with a binding undercoat and then lime-cement plaster, followed by sanding and painting?
2. what time should realistically be planned for a 4m^2 wall?
3. On one side, the wall borders plasterboard (yes, the proper wet-room stuff - the builders did most of that). How should the plasterboard wall be prepared, prior to filling and plastering the area near/adjoining it?

Bonus points if anyone has a solid book or reference for plastering. My library has little on this…