You should also consider a Hagerman Trumpet MC. I have a Soundsmith MIMC, and tried it at 470 and 1,000 (Hagerman has a good range of loading options). I actually prefer 1,000 with the MIMC. On my rig it really allows the MIMC to ‘shine and sparkle’. 470 is just a tad too laid back, but really depends on your other equipment/speakers.
Just keep in mind Peter recommends a minimum of 470, but you can go higher. If I had a variable option on the Hagerman, my feeling is that around 800 might be perfect with the MIMC….on my setup.