Mo'I from GHK, pouni ono from KWK, the 11yr waka from BHK is pretty heady but to some it can be heavy in higher dosages so that ones a hit/miss if you want strictly heady.
Oddly, Kava Supreme is heady for me and it's supposed to be heavy but I'm weird I guess. Puoni Ono is nice because it's heady but not too much. I would be anxious if it was more heady.
I get really nice heady effects consistently from most all Tongan kava I’ve tried. The most recent Kavified Tongan is nice and heady. I can drink it for hours and never get too drowsy.
Oddly, Kava Supreme is heady for me and it's supposed to be heavy but I'm weird I guess. Puoni Ono is nice because it's heady but not too much. I would be anxious if it was more heady.