LibramBurn is great and i use it all the time! However, recently while trying to spelunk Fernswarthy's Basement it kept tripping me up on the "Festering Powder" adventure. As a workaround i applied the attached patch, which allows the "minmp" setting to be a percentage. I set libramburn_minmp to 80 and libramburn_minmp_is_percent to true, and now at least it doesn't burn away *too* much of my MP before that adventure.
Obviously i still might need to turn it off entirely in some edge cases, but this is good most of the time. I haven't really tested how this interacts with MP auto-recovery (since i don't use that) and it probably needs further testing / bounds checking, but IWFM, YMMV.