How thoroughly did you dry those GH blends? Did they come in bulk or tin? The menthol is more present in stuff with green labels I believeI haven't smoked as many G&H blends as the OP. I have smoked Dark Flake Scented, Black Irish X, and Brown Twist Sliced, and detected 0 menthol in any of them. I find this unusual, because menthol typically has a pretty strong presence.
Btw, forget Kools and Newports. If you want menthol, get yourself a pack of American Spirits in the dark green box.
(I've been known to smoke a menthol cigarette on certain occasions that involve, shall we say, a lack of sobriety.)