When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
to be honest I dont think you can. If you want to make it stiffer there are adjustments on the top of the shock if you already set that to the stiffest point already and its not stiff enough get the Blistein PSS coil overs made for the GS430
As it needs to be regulated /measured, I don't think it is as easy as just adding it in and hoping for the best otherwise they would have different pressures.
The shop locally here has a conversion chart for the Advox. You may want to try to call them.
18062 Redondo Circle
Huntington Beach, CA 92648-1326
Phone: (714) 698-8300
Fax: (714) 698-8301