Split tail allows you to connect a lanyard and retain tailstandability. Not useful for me as I always remove the lanyards from my lights.
If you do find a way to implement the FastTech pocket clip, I’d highly recommend putting shrink wrap around the clip. It prevents wear on your pocket where it is clipped, and keeps the thin/sharp edges of the metal clip from scratching whatever you bump against. It’s saved the paint on my car several times…
Another possible option: FastTech has just added the Solarforce pocket clip to their lineup. A bit more expensive at $5.20; not sure if it will fit the Convoy S-series lights though. Also, wouldn’t allow the deep carry I prefer.
https://www.fasttech.com/products/1/10017643/3616400-solarforce-pc2-led-flashlight-pocket-clip
The anodized tailcap threads on the S-series lights mean this would prevent normal use of the switch, as it would effectively lock out the light when installed. You would have to remove the anodization or carry the light head-up, assuming it would even fit.