Something to add with the time it takes to reach rank 12 with the MG. The more you interact with it, the faster the rep is acquired. So if you are doing nothing but killing monsters to get rep, then it will take around 60 hours to max it out. Which isn’t really that long.
To be more specific, each favour you get (from XP) grants 2 reputation, each favour you spend also grants 2 reputation. So if you don’t spend it, it will take twice as long.