Reducing of Docker engine size

Hi all.

I have an inquire to build small size of docker engine.
gihub hub of moby provides building script to build dynamically.
However the size of dockerd is still big I think.
There is building option before running the script like exclude_graphdriver_aufs is not be decreased the size properly.
Is there any option to build for downsize docker engine?
For example, In my project no longer use swarm, how do I remove in docker engine build?
Or other ways of building for reducing size?