Design build, owner build or combo

[Katie Jane Charan]

I'm looking to build our sfr home or a type of home and adu or duplex to offset costs of entire build. 

in order to save costs is it better to do dB or dbb and risks of both options. 

Really looking for a splittable lot, full rehab house  or a lot I can build a twin home on. 

Any suggestions on where to get an advantage to look.