elliptical rudder questions

[kerk fisher]

Our yard is ordering a new elliptical rudder from Ruddercraft. We have a 1990 open transom wing keel. 
Is there a preference between the HDPE or Fiberglass.  Does it really make a difference?
I notice that there's a choice of a 48" or 58" trailing edge.  Preference?
Thanks

[kerk fisher]

Oops.  I see that the elliptical for the wing keel only comes in 48" trailing edge (of course).  Kerk