I'd say trust your ears. If 8 sounds good, use it.
My sound is very bottom-ended, probably because I use midrangy pickups a lot. I have my mids around zero-4 on my MP-1 Classic (Different animal, BTW) all the time, while my bass is around 8-12. My highs are usually no higher than 4. Mids are scooped for some patches...sometimes down to -8.
Of course, it all depends on what amp, what speaker cab, what speakers, and the aforementioned guitar construction you have. I have taken some patch settings from folks here on the Forum and they've sounded fantastic, whereas I have also gotten absolute crap from others. Just depends on the rig & the recipe.
Chorus usually brightens my mix up, sometimes good, sometimes not so much. There may be a patch or two where I get quieter when adding it, but that depends on how high I have the overall mix of that effect (in my rig). YMMV
There are a LOT of guys using MP-1s around here, somebody will chime in with the secret for you.