River Supply (and currently closed.)
Looks open to me and I just ordered from them a couple of weeks ago.
RE: recipes and reducing the flavor level, I don't understand how these high flavor recipes persist. 10-20% flavoring is too much except for tiny vapes. The flavor manufacturers themselves recommend as little as .5% and that can be plenty for total flavoring with a couple strong flavorings. 3% is about the max except natural extracts.