My favorite is a 'comb' just a piece of metal with a dozen 1/4 slots cut
along the edge. Mounted about a foot or so ahead of the rudder pivet point.
On the bottom of the tiller is a ~3/16" metal blade perturding downward and
just above the comb.

Just the push the tiller downward into the slot that best suits your tiller
position. If your afraid this might interfer with normal steering, then put
the comb on a hing so you can fold it down out of the way. (normally I would
have enough friction in the tiller pivet so it stayed above the comb).

I don't have that on my present boat but I'm looking for a similar method.
Right now I just engage the windvane steering control line to either lock
the tiller or let the vane steer for me.


--
My opinion and experience. FWIW

Steve
s/v Good Intentions