I use AmsOil fork oil.
The stock oil in the '06 Shiver forks very closely matched the medium fork oil viscosity, so I use the AmsOil medium fork oil in my '06 Shiver forks and it works very well.
In my '01 LTR valved WP forks I run a 50/50 mix of the AmsOil medium and light fork oils and it works well. The light oil by itself was too light allowing for an overly quick rebound even with the clickers cranked way in. That is why I went to the 50/50 mix.