Awesome! Good luck! here is my experience
I tried everything with my MPP (first owner upgraded to .400 .. )
Gave up and decided I would try a older unit... I bought a damaged unit and after repair, I downgraded to .700 first try... hmmm. One thing is repaired unit had .300 to start with. Maybe thats the diff..
There is a modded 1.4.300 with the limitations removed... i might give that a go... will report back.