i agree with fwacho.
after getting about 15 heart stones, and roughly over 40 other notchin items, I found the end of the forest the best place to absorb them.
Put and of the 5-6 effeciency ones, three at a time, in two battles, theyre done.
you can get 6 or 8 battles before the CTP decreases to 8, which makes it a battle longer, and so after the 6 or so battles, theres a save point, warp out, then go back in. It took me a little over an hour and a half to absorb a large ammount of notch items.