These pics are from 2004. The winchers were a previous owner purchase that I re installed.... used them for 5 or 6 months, then gave them away. Glad I didn't spend money on them. I don't recommend them at all.
There is no self tailing feature because there is no stripper arm to peel off the line. That makes them useless as a sheet winch....in fact, performance will be impaired because the drum must be fully loaded to engage the "st" ribs on the bottom side. When you throw off the line to change tacks, you must unwrap, rather than "pull up" on the sheet to clear the drum.
As a halyard winch you can get a little self tailing action... perhaps 1/3 turn.. for minor adjustments... but you still have to re-cleat the line.... so.. what's the point? The Cunningham serves better for small luff adjustments. Note that the halyard in the middle picture isn't even using the wincher. Especially no good for single handing.
If you're looking for a cleat.... install a cam cleat on a riser. Way more efficient. You can uncleat with one hand sitting from across the cockpit... with the wincher you must sit or stand next to the winch and unwrap the sheet from the cleat part before making any kind of adjustment... it's awkward, slow, goofy.
These things will not enhance your sailing experience.... invest in non captive(no fairlead) cam cleats on risers for sheets and rope clutches for halyards. Trust me.