The Visual Presets guide says that as an alternative to using a JSON file, "the user can also modify the settings via the Advanced Mode menu and save a customized user preset."
Yep, you can use one of the presets like so:
PipelineProfile profile = pipeline.Start(cfg); var depthSensor = profile.Device.QuerySensors(); if (depthSensor.Options[Option.VisualPreset].Supported) depthSensor.Options[Option.VisualPreset].Value = Rs400VisualPreset.HighDensity;
I think that the list of presets might not be finalised though; I read in the comments of one of the samples that they might change. Keep an eye on it when new versions come out!