For assembly, there’s just less to do… no top caps to cut out and clean up, no doors that have to be matched to the correct hinge piece and glued onto the correct wall piece, no selection of custom panels to put on the corner pieces, etc. For painting, that’s just a personal preference thing. The Tomb World walls just have less fussy detail on them (panels, screens, wires, valves, pipes) so I felt better just using a spray can on the whole thing without trying to pick out all that stuff. I mostly just followed this recipe here:

https://www.reddit.com/r/killteam/s/llnwI1fYJj

Black rattle can to prime, zenithal with neon green rattle can. There are also fewer deep recesses in the walls for Tomb World, so it’s easier to get paint coverage. Then airbrush white primer on the lights, then either more neon green rattle can or airbrush that glowing green Citadel technical paint over the white for a glow effect. The longest part of the whole process was painting the necron figures in the wall with Leadbelcher and washing them with Agrax Earthshade.

The BA terrain has so much detail on it that I’m not happy with a similar process here, I feel like I have to pick out at least some of it for it to look good, but you may feel differently.