Lately I've been playing (in big band) a couple of 'jazz waltzes' - namely All Blues and Bluesette, as references - and one of my own compositions. They're written in 3/4, but always get counted in using two bars. Sort of making them more like 6/8, as they're none of them slow 3/4 tunes. I keep thinking they ought to be written as 6/8, but they're not. Is the reason that 3/4 is maybe easier to write and read, even though every 2nd bar only has about the same emphasis as the 2nd half of a 6/8 bar? My tune has that same feel as well. I guess there's the possibility of 6/4, but they're definitely written in 3/4, although I've had a trawl, and All Blues appears to be in all three incarnations.
Question is, which is preferable for a standard jazz waltz, and for what reasons?.