I have to frame chimney chase at place of “fake chimney”. It will be around 22’ tall. Will do photos of place tomorrow. Is it better go with 8’ 2X6 whit top plate and then build another wall at top of this (inspector say I can go 2X4 for upper part 16’ long). I think it would be more solid to do balloon framing. 2X6, at top of it 2X4 and join them with some 2X4 4’ or 6’ long, no top plate of 2X6 and seal plate of 2X4 between them. Of course 2X6 part have a lot surface to attach to existing framing. 2X4 part will just rise in air.