Ok, so if I do scaffolding since I want to build a huge wall, what would be the fastest way to destroy them? I can't just let it "fall down" since it's all attached to the wall..
[Edit: darn, didn't answer
thisquestion, and went off on tangents. Will make another reply, sorry.]
If you're building a wall, on top of another wall without wanting any flooring either side to stand on (or dedicating time to making a set of temporary bridges), then your big problem in designating the 'ontop' walls is that dwarfs don't like to stand on spots were other constructions are to occur and (if you let them, and don't keep an eye on directional preferences) they like to hem themselves in. But with a little micromanagement you can get them to do it more logically.
Say you've started with a square enclosure that you want to operate on from the inside. e.g.
.......
.#####.
.#...#.
.#.>.#.
.#...#.
.#####.
.......
And you want to build on top of that for an arbitrary number of levels, depending on how many builders I wanted to apply to the task at a time, I'd take the upper level and designate the following wall-blocks on the next level up (with the given stairway accesses needing the lower level, of course).
1-2 <=4 <=8 12-20? (large enclosure version)
O++++ O+++O O+O+O O++OO+++OO++O
+X + +X + +X X+ +X X X+
+ + + + O O + +
+ + + X+ +X X+ O O
++++O O+++O O+O+O O O
v v v + +
#++++ #++O# #O#O# +X X+
+X + +X O OX XO + +
+ + + + # # O O
+ O O X+ OX XO O O
+++O# #O++# #O#O# + +
v v +X X+
#++++ #+O## O++OO+++OO++O
+X + +X # v
+ O O O #+O##O+O##O+#
+ # # X+ +X X X+
++O## ##O+# O O
v v # etc #
#++++ #O### <=
+X O OX # TR and BL corners
+ # # # can now be started
+ # # XO on the level above
+O### ###O# <=
v
etc
v
#O###
OX #
# # At this point you can start
# # this corner off on the level
##### <= above (after the stairs opposing)
As you can see, the more simultaneous points you want to start at, the more stairwell scaffolds you need, but you can balance it so there's just the one (but only two dwarfs can work on it at the time) if you don't want to flood the site with scaffolding and (apart from doing the most inaccessible corners first, which is essential unless you want to fudge that by using external scaffolding later).
The "start the level above" hints are only useful if you have extra workers available, but you weren't keen on so many stairwells. But beware of the Last in First Out nature of construction, because one or two workers (in the first column) may build the BR corner on the level above before attempting the two final ones adjacent to the TL corner, and then you're tempted to assign the next two in line adjacent to the BR corner on Z+1, but you still need to make sure you put the TL standalone in on Z+1 before you forget, so need the standing space afforded by the TL-adjacents. IYSWIM.
Obviously the above is scalable, and you'll need to adjust. I see you mention building a cylinder, in which case you need to ensure the walls are
### over- and on the level above will ##O before ###
### lapping need to do something like: +++ you do O++
I see some people mention putting in temporary floors to access the corners. While you aren't doing it, this is something I find I often need to do when I'm building overhanging bits (e.g. minimal footprint walled-off 'stairwell shaft' punching through ground level, but wanting to use far more elevated real-estate).
OOOO wait ##OO before ##OO now ##OO
x+++ ++++ until ++++ you +++ you O+++
+++ -> O+++ -> O+++ -> O+++ -> O+++
++X O++X at O++X remove O++X can O++X
+++ O+++ least O+++ this O+++ add O+++
But once you have the overhang, you can build on the level above as per above "on top of walls" instructions. Or if you're flooring off every level, then just need to worry about all the corners. One of my favourite 'tower' designs has the following type of floorplan (to differing scales... with differing room sizes and stairwell areas produces different skews, to interesting aesthetic effects. I've got it down to a fine art)...
#######
#+++++#
#######+++++#
#+++++#+++++#
#+++++#+++++#
#+++++#+++++#
#+++++###+#########
#+++++#+++++#+++++#
#########+###+++++#+++++#
#+++++#+++++#+++++++++++#
#+++++#+++++#+++++#+++++#
#+++++++++++#+++++#+++++#
#+++++#+++++#+#############
#+++++#++++++X++++++#+++++#
#############+#+++++#+++++#
#+++++#+++++#+++++++++++#
#+++++#+++++#+++++#+++++#
#+++++++++++#+++++#+++++#
#+++++#+++++###+#########
#+++++#+++++#+++++#
#########+###+++++#
#+++++#+++++#
#+++++#+++++#
#+++++#+++++#
#+++++#######
#+++++#
#######
In the above, I have to worry not only about 12 external corners needing a temporary floor to access, but 4 "middle of a cross" wall sections that need helping out (at each "inner angle" of the three-room 'suite' layout). But once I've gotten the first overhanging level sorted out, access to Z+1 and any flooring out from the stairwell that's needed to access the wall-tops, then I generally assign to be built all the room floors then (to take priority) all the 'junction' walls (internal and external corners, plus where there are 'T's in the walls), then (to take absolute priority) the floors in the 'doorway' squares above the gaps in the floor below(although I needn't technically do that, if I'm careful about not blocking anyone in on top of the wall-spurs later on). Then I can start designating the non-corner walls to be built as soon as the floors reach them.
If I'm planning on gaps in the external walls for windows (or other things like inter-tower walkways) then I will of course have to contend with those design issues as well.
This does not seem to apply to the OP's question, but I thought I'd share.