I think that big complicated structures like incoming reactors and cooling towers and Mark2 steam engine should not be built by hand but rather by some sort of automated system.
Player should provide materials that other machine will built. Buildings will be placed and will await for materials.
I think construction can be made in three ways:
- Construction robots
Buildings will be made using construction robots and materials will be taken from player or logistic network. Possible problems with one of achievements forbidding use of logistics.
A special crane will be constructed that will be supplied by simple box and inserter. Crane will have its range of functioning so it has to be placed in right spot to work.
This will work like a huge inserter.
- Building itself
There will be gantry crane placed when player specifies where structure should be. Simple wooden crate full of materials and inserter which inserts materials to the gantry crane. After finishing crane can stay or be consumed by building.
I can also see this as a crane that is put in the middle of the structure and raises with building and is left there at the top.