[Cohen]

It's right 25 Pearls.
For all the 8 paths you'll spend 15 gems and 2 slaves. And usually you lack of some king of magic to site search via magic and you've to waste time sending your random pick guys to site search for 1st tier magic sites.
Then you use 8 mages, so on 8 research/forging/battle round wasted for that/those mage/s.
Then you don't site search for Holy and Unholy sites, but they're so few that usually they're not so important. (however having the luck to find tha undead burning site in a chokepoint of your borderline with Ermor is useful but it works even if you don't discover it).