On different basses and straps, I use Hennessey, Loxx, Dunlop, Schaller, Grolsch, Dimarzio clip-locks, locking straps from LM and Planet Waves, and bolted-on straps.
The Hennessey's work well, but feel a little cheap. You can use a regular strap with the pins, but it won't stay on well.
The Loxx are the best in terms of locking and ease of use, but you absolutely can't use a regular strap. Plus, they are the only ones that I had to cut the strap to make them fit. The strap fits nice and close to the body of the bass.
The Dunlop's are good and can use a regular strap, but if you are careless, it is possible to think you have them locked when you don't. (I always give them a little tug to make sure.) the dual designs or classics have the best pins for a regular strap, but with the locks, the strap is oddly far from the bass body. This hurts nothing, but looks funny if you care about such things. Dual designs do look like a regular strap pin, but the are a very large pin. The classics are harder to find, but a little prettier pin.
Schallers are secure, but can come loose from the strap and I have had noise between the pin and the lock come though my amp. The coming loose problem is easily fixed, but if you experience it, they fail open instead of failing secure.
Grolsch are great, but a little hard to get off and on and easy to lose.
Dimarzio clip locks replace the strap pin with a clip, which is secure, but I worried the clip would damage the finish while in the case. Plus, a regular strap is out of the question.
The LM locking strap eventually wore to the point it had potential to pop off the pins. I also modified it with some mole skin so that the plastic surface that rubs the bass wouldn't scratch the finish.
I really like the Planet Lock straps, but the strap selection is a little limited, and there are some basses where the pin placement prevents you from using them. I always keep one or two of these with me, though, because they are pretty close to a universal fit. The design has improved over time, and the surface that can contact the instrument is now soft rubber instead of hard plastic. I am not sure if the rubber will damage nitro finishes or not.
The bolt on strap is a good option is you never want to remove the strap again. I use this approach on an old, road weary bass where I needed a very long bolt to get the strap/pin to stay in the wood.
I think the question was about pins for a thunderbird. I use the Hennessey's on my 'birds. The top pin is on the back of the bass, and I chose the model where the strap part is fairly flat. Loxx would be a good choice here as well. Dunlop would be my third choice here. Because of the position of this pin, I could see a Schaller "poking" you, as mentioned in this thread. If the front pin is on the end of the body behind the neck, the Planet Lock strap won't fit. On my NR bird, though, I use Dunlops with classic pins, just becuase the classic pins look most like the original pins, and I wanted a wider strap than is available from Planet Waves.
