I really like the divide by 2 and disable with a button method, it's simple, easy to tell your drivers, and works quite well. You can also pick any other number than 2 if you want, like 3.
Some teams, like us, have cubed the joystick values (that is, x^3). This allows you to have slow speeds the majority of the time (that still increase), but also allows you to have that last bit of full speed. Squaring works, too, but cubing seems to be better and more defined.
Visualize it with this graph. Plus, you don't have to press a button to disable it for full speed. Sometimes, that's one more button to memorize and drivers get turned off by that and don't use it.
To program this in LabVIEW: squaring is as simple as inserting a Square node in the wire. Cubing is more tricky, I would suggest using a
Compound Arithmetic Function set to multiplication and the same joystick value wired to 3 inputs. Or you can use a fancy
expression node, but don't forget to use ** instead of ^