That would all depend on what shocks you have... The "most correct" way to set your shock would be to place the bike on the centerstand (allows the rear to hang free) -- then measure the distance from the bottom of the brake rotor to the frame under the saddle bag (the height value).
Next remove the bike from the center stand and let all the air out of the system (0-kPa). With you (or a friend) sitting on the bike measure that same rear height measurment (rotor bottom to saddlebag frame) while you add air to the rear shock. Use the air to adjust the height to be 2.75" (~7cm) lower than the measurement made while on the center stand.
Make note of the pressure needed for this height with the bike loaded (you on the seat); that is a good place to begin experimenting.
This 7cm value is ~ 30% of the suspension travel, so there will be 60% more travel in compression to provide a nice ride. This approach can be done for any manufacture of shock.
Hi there can i ask you a question I just bought a 1996 SE and the rear shocks on dash is in kilopascals I weigh 200 lbs what should the reading be for highway riding. The owners manual is not very clear