So i got the Shimano CS50 (flat backed cable stops for DT shifters) in the mail and completed my Suntout Symmetric Shifter conversion. After grinding / buffing down the right side of the Symmetric shifter body, the CS50's fit perfectly.

ONE CONCERN: the VERY fine pitch threads of the 2 bolts that hold the shifters on are REALLY short. They fit, and they hold on the cable stops, BUT there are only a few threads in the shifter body. I used lots of lock-tight on my install and i did not use massive pressure when snugging up the bolts.

i dare anyone here to find this bolt aftermarket: M5-.050 X14mm. that is what you would need to get some extra threads into the shifter cams. the stock bolt is an M5-0.50 X9MM and is impossible to find. M5-0.80 you can get all day long.
the thread pitch is wacky on the Symmetric shifter...

Anyway, here are some pix all finished... I pulled the springs and plastic barrel adjuster off to make it a little more low profile, besides the barrels would not turn as they sat tight against the frame.