Well, I went for a Yuki 7206. After some modding it didn't turn out too bad. You'll find the story here:
http://rwg.cc/topic/177949-yuki-7206-bracelet-no-longer-accepts-gen-spec-bars#comment-1450950
My mistake, typing error. Apologies for the confusion. To seat the Athaya tube snugly, I used a 6.3 mm x M3-90 degree countersinker first to create the sloping 45 degree angle. Then a ca.3.2 mm drill bit to widen the hole ever so slightly to a depth of ca.0.3 mm. This creates a small step and angled sides for the tube to sit in. I then cleaned, and extended, the remaining case thread carefully using a M3 x 0.35 tap.
Guess I was lucky with my WSO 580s, last ones I bought were a few weeks ago.
If you don't mind the inaccurate open access to the springbars on the Cartel 580s they'll do the job. However, they are an easy tell to spot off the wrist.