GStreamer Editing Service for Rust / How to specify encoder settings - encoding

Question

I'm new to gstreamer-rs. I try to render a video using GStreamer Editing Service. At the moment I am using the example code for encoding profiles as follows:
let p = gstreamer_editing_services::Pipeline::new();
let t = gstreamer_editing_services::Timeline::new_audio_video();
p.set_timeline(&t);
let l = t.append_layer();
// Every audiostream piped into the encodebin should be encoded using vorbis.
let audio_profile = gstreamer_pbutils::EncodingAudioProfileBuilder::new()
.format(&gstreamer::Caps::new_simple("audio/x-opus", &[]))
.presence(0)
.build()?;
// Every videostream piped into the encodebin should be encoded using theora.
let video_profile = gstreamer_pbutils::EncodingVideoProfileBuilder::new()
.format(&gstreamer::Caps::new_simple("video/x-h264", &[]))
.presence(0)
.build()?;
// All streams are then finally combined into a matroska container.
let container_profile = gstreamer_pbutils::EncodingContainerProfileBuilder::new()
.name("container")
.format(&gstreamer::Caps::new_simple("video/x-matroska", &[]))
.add_profile(&(video_profile))
.add_profile(&(audio_profile))
.build()?;
p.set_render_settings("file:///tmp/my.mp4", &container_profile);
The code is working; but I do not have any clue on how to enforce specific settings. Maybe someone can help.
How do you set things like bitrate, framerate and quality options for the audio and video encoder?
How do you define a specific encoder (like nvenc/nvh264enc for h264 video)?