Values according to valve are:
ff_damage_reduction_grenade 0.25
ff_damage_reduction_bullets 0.1
ff_damage_reduction_other 0.25
ff_damage_reduction_grenade_self 1 - there is no default value.

I think we should leave nade at 1 given how low damage they are compared to cs:s. These changes are live, let me know if we need to adjust the ff further.