When I use pins, it's back over front, and almost as tight as possible, as already pointed out here, they will loosen up some in the wearing and wetting. Most times with pins, I use 4, 2 each side, this helps keep the waist snug as well as at the legs. Although, sometimes I like to just use 2 pins, and get that loose feel in the legs.
I also like the snappies lots! The size 2, or toddler size are great! They really hold well, and keep things nice and snug.
I have some Boingo Diaper Fasteners too. They do well, and are more like a traditional safety pin, but redesigned. They have the ability to flex and pull, where as a steel safety pin will not. You can find them around, if you google, and at Changing Times too.
It depends on my mood, and how I feel, as to which method I use, and choose.
It's all good!