Rather than spend $100 on a tiller lock, I'd seriously look at a tiller pilot.
Back in the day, we had a Tillermaster we used for years. My memory is a bit faulty, but I almost think that it was developed and built initially here in the Tacoma area in the early '70s, but I can't be sure. The Tillermaster was crude by today's standards, but it did what it said it would. It would hold a consistent compass
course. Current tiller pilots are a lot better, both in their mechanics, electronics, and water resistance. The advantage with these is that it will hold a heading, and not simply a tiller position. Back when we would need to go to the bow to put on or change a hanked on jib
, it was nice to be able to do it knowing the boat would maintain a consistent course.
I'd look at something like the Simrad TP10. It will cost over $300 more than your tiller lock, but I think will end up being a lot more useful. They are easy to simply pop on the tiller and set. (one thing I liked about the old Tillermaster was the rotary knob for adjusting course).