Spring rate should be around 0.60 kg for most riders and loads for adventure riding on the BMW F800GS. Lighter riders can use 0.55kg. Traxxion sends the units out with 7.5 W oil and recommends around 125mm fill level.
Changing the weight of the oil will increase the dampening rates at all levels. Increasing the fill level to around 100mm will provide more bottoming resistance at the end of the stroke. Either way if you need to adjust the high speed dampening only the best way is to send the cartridge in for a internal parts swap.
2013 Ducati Hypermotard SP, 2011 Husaberg FE570S, 2011 BMW S1000RR, 2010 BMW F800GS
2007 Husqvarna TE610 , 2003 KTM 525 MXC