GM, i would like to say that, erm....
You can change the monster in a MAP, and that map is onli spawn like Skelegon or something.
and add bosses in FM in rm2 rm3 and so on.....
As example:
I(454 times rebirth), i want to be train faster, so i can go to FM room and kill bosses such as Zakum, papulatus, pianus.....
A suggestion,
Use Purple Plain , use that map to spawn ONLI Skelegon, then it will be easy to train, and 1 thing, the spawn rate must be VERY FAST!
thats all....