On the subject of tracking, this tool is by far the best I have ever come across for ease of set up:

http://www.gunson.co.uk/product/G4008

Prices vary and a short internet hunt will bring the cost down from that shown in the link above...

The camber, castor, any king pin inclination, all influence the pull tending to open the wheels. The degree of spring in system a factor.
All a bit academic with Sevens because of the coarse adjustment (unless, as often, the track rod is deliberately bent) I dunno how owners consistently get high tyre mileage from Sevens without some brutal bending.

There can be few cars more simple to check and measure than Sevens. For moderns really need an awkward external calliper contraption as so low.

On cars with significant tow out, an annoying conscious effort is needed to initiate slight turns.

Location: Auckland, NZ