1. You can use global_npc.pl in your global folder to do global NPC drops on NPCs above level 51 like this: 
	Code:
	sub EVENT_SPAWN {
    if ($mlevel > 51) {
        if (quest::ChooseRandom(1..100) == 1) {
            $npc->AddItem(ID);
        }
    }
}
 2. #npcspawn create creates a new NPC which explains why it copies some data. It also adds a spawn entry based on that new NPC. Try using #npcspawn add and modifying the spawn time that way.