Ghost Hunting: Finding Spectres ...

Hi

I like Sentinels but feel Alchemists do the most dmg - I have desecrate up to lvl 75.

Question is - how do I get lvl 73-75 Alchemists using desecrate without having to go to wastepool maps, which is where i normally get
them from?

Any thoughts on getting spectres quick would be great, because I lose them when I get logged out.

TY

Turnip