I would start with the MP4 Normal or MP4 fast profiles as a baseline. Copy it into a new profile and rename it so you can pay with it and not have to reinstall MCEBuddy.
The other place to see how parameters are built up can be seen in this post.
You should also look at the advanced commands post and refer to the section on hardware optimized profiles. That tells MCEBuddy not start replacing parameters as the profile is optimized by the user.
The setting name is
UsingHardwareEncoding=true
Check out the other advanced settings for video and audio which maybe helpful.