suspension brackets / steering rack woes from a new builder

[Ifix]

Hi guys,
Started building about a week ago, and I'm currently up to the point of making the suspension and shock brackets but noticed that the drawing seems to be wrong (or I'm missing something) for the shock bracket should the radius be 20 or should the overall length be 122, as I don't see how they can both be right? also I read on here somewhere that the backets needed to be modified to accept the shocks (is this due to the same problem I'm experiancing?)
Secondly I'm a bit confused about the escort steering rack thing. I get that the sierra rack is too long, but the book says that 'for absolute precision modifications to the rack are required' What I don't understand is that if I'm going to the trouble (and expense) of purchasing a new rack and making extensions then what else can be modified on the escort rack that I can't modify on the sierra one (if that makes sense) Sorry for the long message, thanks