There is a huge difference in the relative weight issue between ferro-cement and otehr materials when you are talking about a 60 foot boat vs a 50 or smaller footer. Properly built, ferro cement is a perfectly reasonable material for a 60 or so footer. It still is a comparatively expensive material to maintain over its life cycle if maintained on an equivillent basis to the more common boat building materials.
Just for the record, while blistering does occur in fiberglass boats built during a narrow period of time, it is not a universal problem within the better built boats of the recent past.
By the way, what year did your boat take a third in the Transpac and how many boats were in its class?