It seems that you found something that I missed. I just pushed a patch to make this available in the next version of Magick.NET that will be published this weekend. Below is an example.
There is and there will not be an option to pass a magick command line as a string. Since all that does is calling methods that are available in the various classes of the wrapper. If something is not there it will be added :)
MagickNET.SetRandomSeed(1337);