As I understand it the mod api doesn't let you control constructors, but it looks like it has enough to essentially imitate them. The only thing I don't know if it has is the ability to read and utilize the crafting times.
My suggestion for how we might work around this:
require an npc block, similar to the gardener (call them an engineer in this case)
reference a constructor (if you can't determine the type needed, just go for advanced constructor)
to avoid completely bypassing the tech tree, craft by referencing an existing copy rather than an id (you need at least one to be able to craft it)
if crafting times can't be read, then assume a longer time and call it a cost of automating it
As I understand it the mod api doesn't let you control constructors, but it looks like it has enough to essentially imitate them. The only thing I don't know if it has is the ability to read and utilize the crafting times.
My suggestion for how we might work around this: