Personal preference really. I turn them to the side but either way you go, they will not match up if you turn them up and down AND right and left.

I would draw a diagram but there are plenty out there already.

If you tilt them all the same way, they should match up - all right/left for example.

When you mix them - there is no way for the edges to line up.

But turning the outer ones in (shouldn't need to as the DS100 is curved anyway) and stacking the top layer the same way.... it should get pretty darn close to seamless between the monitors.

Post a pic perhaps?