It depends what track you are using them on.
If you want to go to Hornby second radius curves (or similar), the 158/159 can use #46 couplings. Simply remove the plastic coupling with a knife or similar to leave a smooth surface, the #46 is box mounted and will sit on the little ledge that is left for the correct height (it is still advised that you get a height gauge)
The Voyager is a different matter because the actual coupling is much higher than the Kadee likes to operate, but if you are willing to compromise that you can modify a #46 to fit and turn enough on second radius curves, by removing some of the side of the coupler 'box', but be aware that this will probably affect the self centreing ability.
The reason this is so is because the Voyager has a long 'nose' compared to virtually everything else. I have set my kadees at a slightly higher than normal height for ease of fitting and retaining as much detail as possible. It sits on the grey box that the moulded coupling extended from, but having already removed that mould.