I don’t use much heavy but always Have good luck with kavatime Ambaes. Art of kava Damu also.
For heady kava we are so blessed these days compared to just a few years ago. Go find your favorite vendor and buy some Palarasul or Kelai. Many vendors carry those single cultivar (Kava Society, N@H, AoK to name some). If Vanuatuan kava isn’t your thing then Malo Tonga from Fiji Vanau is great though not the headiest Tongan I’ve ever had it’s good for mixing or by itself anytime.