The only one I'd recommend for sleep, and I've tried Quick Kava/BKH/Shaman/Paradise/Ozia/Kwik Kava, is Chris's (Gourmet Hawaiian Kava)'s Vanuatu. The rest of those either didn't really sedate me or didn't do much.
Well, here's a rough "ranking", but really like kavadude and Deleted User01 said, GHK's is really the only one I would use, though I have found that the Kava Candies are nicely relaxing and not as surprisingly kavain-y. "Kavainy" should be a word
Gourmet Kava Instant
Ozia
Shaman
Fire Island
BKH Green
Paradise
"Kavainy" is a good word. I get tired of typing in "Heady". "Hey, look at that guy with the big head, he's heady." See, that word is too wierd. We could use Stony? But that has bad connotatations round here.