After my group missed a few treasures like this I put a post-it note up that said don't forget to loot the bodies. The only problem now is they strip every body (he he do you see what I did there) down to their skivvies looking for loot.
But to answer your questions
1. I spread it through out the dungeon with about 40% in the last room or encounter area.
2. I tailor some pieces that I know the PC's are looking for or what I think would make their characters more awesome. That being said if I have a pc that is constantly using one type of potion or scroll I don't provide one in every dungeon they should make/buy their own.
And back to the topic, the rest I roll randomly for which is why I can't wait for ultimate equipment
I'm excited to see what they do with a +1 human bane shovel.