Rear Wheels Towing in

[Enoch]

Hi Folks, I have just test fitted my rear suspension components. It all seemed to fit together very nicely but on checking that the uprights were parallel I notice a slight tow in. It's the same on both sides and it's only very slight. When I put a straight edge against it and measure the distance from the bottom rail to the straight edge it runs out about 2mm over about 1 metre.
So 2 questions really:
1. Should I worry about a tow in of that much?
2. If I do need to worry what would be the best way to fix it?

I was thinking of thin shims between the donor hub and the upright - does that sound sensible?

Oh bother - that's 3 questions
Anyway - your thoughts would be much appreciated.
Best to all,
Enoch.