Well, if months and zodiac signs affect the chances affect the luck, I would just keep reseting. In my opinoin, it would be a waste to be walking around until I have my unit/monster with X sign in X month to have X item. If I can get them reseting and not wasting days, the better.

Yes, dragon whisker is good and best in situation spear until nelveska temple. But Holy lance is still my personal favorite poached item. More easier to get, nice attack, and I always some fighting mages in my party.