(usually i would not suggest this) camber adjustment can be done by using thinner shank bolts on the top of the strut, or by enlarging the holes in the turret that these bolts go into.
there are 3 bolts, the ones you need to remove when you are removing the strut. if you use thinner bolts, or enlarge the holes, you can move the top of the strut to adjust the camber. you need to move the strut towards the wheel.
you can use a magnetic camber gauge to find the current camber, and also use it to ensure you set the new camber at the correct degrees. this tool does not cost much, mine cost £30.
i would be lying if i said i have never done this to cars in the past, but i cant honestly say that it is a perfectly safe thing to do. the turret is specially designed to take the force of the strut and spread it in a way that will not compromise the turret's welds. if you move the strut off centre it will mean the forces acting on the turret are no longer occuring in the correct place. worst case scenario you will snap the weld at one side of the turret (not good)
however there is a safe amount you can move the strut, and thankfully this is about the same amount you usually need to move it to correct your camber (depending on how much it is lowered obviously).
its hard to say which method is best, but personally i would recommend you enlarge the holes by 4-5mm, add larger washers to the bolts, and then bolt the strut in place as close to the wheel as you can.
EDIT: i'd just like to add that any death, injury or damage is not my responsibility. always seek the advice of a professional