I also have an MIMC Star, and have found the loading of 1,000k works best for me (wish I had the option of around 850 though, and 470 lacked a bit of 'sparkle'), and my gain is set at 60 dB. My setting on my Hagerman Trumpet MC provide a variety of setting for MC, and these are what I have settled at.
Provided as an example from another MIMC user.