Hi,
Perhap you could contact Festool nd get them to swap out just the rail under the 30 guarantee. I can't imagine that Festool would want to take back the saw and rail if they could just do the rail. This swapping under the guarantee idea may seem like it is taking advantage, but the fact is that it is legitimate to be dis-satisfied with the 55" rail in combination with the 75 saw.
If you have to pay shipping both ways though, you may as well just buy the 75" rail. You will probably want the 55" anyway. For shorter cuts just because it is handier.
Seth
Perhap you could contact Festool nd get them to swap out just the rail under the 30 guarantee. I can't imagine that Festool would want to take back the saw and rail if they could just do the rail. This swapping under the guarantee idea may seem like it is taking advantage, but the fact is that it is legitimate to be dis-satisfied with the 55" rail in combination with the 75 saw.
If you have to pay shipping both ways though, you may as well just buy the 75" rail. You will probably want the 55" anyway. For shorter cuts just because it is handier.
Seth