I have not used the Turtle Wax products you listed on headlights, but I have used other brands' equivalents to those with satisfactory results.
The TW stuff is probably less abrasive than most other brands, so you may have to work it longer and/or use more of it, but the end result should be the same.
Also, you will want to seal/protect the plastic once you have de-yellowed it, so either get some headlight sealer or just use some synthetic wax like Meguiars or Mothers.
FYI: I would not suggest using these products to clean the lenses by hand; I would use them only when you have a polisher/buffer to do the work for you. Otherwise, you will be working very hard to achieve anything satisfactory as far as de-yellowing goes.