Suspension

Hi c-hings,
Finally I bought a SCX10! really enjoyed buiding it from zero! I follow the menu step-by-step and completed now;
however, I found that the suspension seems too hard (each wheel is not moving up and down very indepedently through obstacle)....I fill the suspension oil fully with some oil spilled out during closure of the cap....

how much oil should withdraw in each suspension tube is suggested?? thank you for the guidance