check that out for more details on PH's . but that lesson explains a more advanced version of PH's. And yeah you dont need a Whammy to get it at grassroots level.
After I tweaked the height of the pickups on my Givson it sounds awsome for metal , gets real classy Pinch Harmonics.
Try increasing the height og your pickups ( bring it towards the string ) , well at least do it to your humbucker . Increasing the height produced more Output hence better Harmonics