I'm sure people would know in afrtermarket upgrades. Because that is where this topic is going! Pleas keep all aftermarket or OEM parts questions or comparisons posted in AFTER MARKET UPGRADES or FIDDY BIKE TALK!
PM 451sdad, he's using 75 forks. The oil level and weight depends on your weight and what riding style you have. Oil level and weight will change the characteristics of the fork, but XR75 forks are typically undersprung and underdamped so stiffening them up likely is a good thing. Again it depends on your style and weight.