Heady and long lasting don't go hand in hand with kava. Heady effects come on the fastest and dissipate first. In my experience the best kava for anxiety relief isn't always the one with the most mood uplift. As far as Kava Tonga, I've experienced the strongest mental effects from that one relative to other tongans but it doesn't help me with anxiety at all compared to others that I'd call milder... like old batches of Tongan Family Reserve or the now discontinued BKH Kula.