help with 03 200 suspension

[XR250R64]

i need help with suspension. i set the sag right along with static sag. i weigh 145 6 foot ireally need to lower seat height some. i ran a harescramble yesterday had a great time was looking at other bikes and seems that everyone is lowering them alot. i dont ride mx dont jump i am really want to start running gncc. i really need to get faster on tight single track. how do i tell which rear spring i have please any suggestions would be appreciated thank you