@deni - You can utilize the WADK from 1709 to capture and then distribute a WIM of 1830 using the existing OSD dashboards. It works.
By Microsoft specifics, to capture/deploy Win10 1803 you need an MDT Bundle built on WADK 1803. In order to do so, you would need to install WADK 1803 on the bundle creator machine. After that, you can run the fixlet to create the MDT Bundle (and later import it and create profile as usual).
Testing is confirming that, as for the latest Windows releases, the strict dependency on WADK version is not really so strict, and capture/deployments on older versions of WADK continue to work. So we were able to capture/deploy Windows 10 1803 using the “GA” MDTBundle built on WADK 1709.