The spacers' width depend on the hub you will be using.
If the hub has a 120mm spacing then you will need spacers that add will add up to 135mm...which I don't have much idea on how will it work out; you will most likely need a longer axle as well, ask your LBS about them.
As for the chainline, a longer bottom bracket length will compensate for the spacing at your rear wheel.
Here's a list.