After we made the big decision to just go ahead and skim coat the entire huge front room, making the same decision in the TV room seemed easy by comparison. The front room is both smaller by square footage standards and it also doesn't have such a cavernous, pitched ceiling. It was a ton of work in the front room, but after we made the decision it really didn't seem so bad, coming to that conclusion was probably the worst part just because we knew it would add so much time to the project.
We decided to skim coat in the TV room to make the texture even because there were some inconsistencies. When we textured the kitchen (our first project in the house) we used a spray and knock-down method. In hindsight, this kind of sucks because it doesn't match the texture of the rest of the house, but clearly we were newbies at this whole renovation thing and we didn't know Chris' amazing texturing skills at making joint compound look like 90 year old plaster walls. As a result, we had a patch of spray/knock-down texture on the wall from when we made the pass through (this used to be a wall that we cut out and matched the arch to the arches throughout the rest of the house to make it look original)
Also, throughout the years smaller patches have been done where the plaster has cracked, so it's a little mismatched around the whole room.
I moved around the room and taped all the cracks and then diligently worked my way around applying a light skim coat to all the walls to make the texture more or less flat (it didn't need to be perfect by any means because Chris would come around once I was done and apply his looks-like-plaster texture)
While I worked on the walls, Chris worked on skim coating the ceiling. After we had repaired patches that needed help reattaching the plaster to the lathe we used a screen across the whole length of the ceiling to help bond the joint compound to the ceiling to prevent future cracks
One side of that screen is a bit sticky and you attach it to the ceiling, then spread the joint compound over it
When Chris started work on the ceiling I was out of the house working on getting trained for some accounting work I'm starting for my brother's company, so he worked in small sections because actually attaching that screen and spreading joint compound over it directly above your head is a little difficult
(that left side is done with a few pieces of screen)
When I returned we were able to work together and spread out one piece of screen the length of the entire room: I held it up while Chris spread joint compound out here and there until there was enough on it to really make it stick
Once it stuck I could relieve my achy arms and Chris could skim coat a nice layer over everything
We repeated the screening process on the lower part of the ceiling as well
And pretty soon after lots more scraping chunks of joint compound off and doing one more light skim coat over everything, we're finally ready for texture!