[draya]

im trying to tone them make them firmer not blocky,is it better to use moderate or heavy weight?

[Moro]

If you want firmer use high reps im saying in the 20-30 range your obliques can handle those kind of weights use a light-moderate weight but for oblique exercises you cant afford to lose your form or you end up working a completely different body part like guys doing woodchoppers end up using their shoulders ill chuck a routine here for you, you dont have to use it but this is what i do.

Dumbbell side raises 3x20 each side
Woodchoppers 3x20 each side
Oblique sit ups 3x30 (15 each side) i like to alternate mine left, right,left,right)

Hope that helps

[Painislove]

def. weighted side bridges and normal bridges.

[ZackKnight]

ZiR would know. his are perfect