Also, how many boxes did any of you open before you got Zin(R), DB SE, Mure SE or Xinyi RE scrolls permanently?
There aren't any "hidden" skill items in the Boss Modes you mentioned. Did you mean a different SE? Since Xinyi Liuhe Quan comes in RE only.
Thanks, I did mean SE. It is hard work to keep track of this RE, SE, R, BK, BF nonsense, so I forget sometimes. Going to correct my original post.
To answer your question, all the scrolls you mentioned are equally as difficult to obtain (as they all require combination formula pieces). You're probably looking at a good lengthy farm for all of these (average of 300, under that if you get lucky). Zin Taekwondo (R) is theoretically the easiest one of the bunch since it has an alternative formula that uses your existing Zin Taekwondo (BK) should you possess it.
Is there a thread for which boss modes give what items ? And if not, does rabbit lair only give rabbit exo ?