i was reccomended lighter fluid although havent tryed it i dont trust my knowledge if you do want new forks and like dj3's try the 03's there soooooooo good!
do some cross training, try doin waits on ur arms and upper body you will be surprised how much differance this will make, it will feel as if they are lighter
its the steerer mainly, and the body of the fork that weigh most. Lighter oil etc wont make a bit of difference. Speed up the rebound and the forks may want to come off the ground easier. If it were me i would be looking into a lighter fork (i did a while ago - got Z150)