But looking at an offset calculator, this wheel will bring the inside edge 19 inward towards the strut, and the outside edge in 7mm, effectively reducing the rear track by 14mm. Also going in 19mm would put it a lot closer to rubbing on the inside, hence the idea of a 10mm spacer. I think that would be the best approach, but I'm looking for info from someone with more knowledge than me.
http://marksink.com/tire_wheel_offset/offset.html