How to I plaster top of walls after removing ceiling?

[a1993h]

Hey all!
I recently pulled down the lath and plaster ceiling in our living room and am wondering what my options are to finish the top of the walls. The bare wall is visible on top of where the old ceiling finished.

I’m thinking of plastering up to the boards that support the joist, which sit on top of the wall. Guessing that if I attach an angle bead in line with said boards and the wall I can fill it in and plaster over?

I’ve done a bit of plastering but definitely a novice. Wondering if this would work and would appreciate any suggestions or alternative options. Thanks !

 

[Wayners]

I'm going to add a bit more information than you asked for.

Fit timber all around the edges. Stops the board flex which will stop ceiling line cracks.

Hire a board lifter. About £40 for a day or £70 for week. Makes job easier.
To answer...
Vacuum and spray water around top of walls and fill with limelite renovating plaster. Its like bonding. Old property so you shouldn't use gypsum?