In a conversation Phill and I had about the fiberglass "faired" spreaders on the older Taipan 4.9's he mentioned to me he had measured the spreader width on another "chap"s" 4.9 and his spreaders were wider. Since I also have a Boyer Auscat CF mast sitting in the barn I went out and compared the 4.9 spreaders I removed from the ones on my Auscat mast (they looked basically the same and I had assumed they were- But you know what they say about "assuming"?!).
See attachment to see the picture of my black Auscat spreaders (on the black CF mast) compared to the white 4.9 spreader- Looked to me like they started out exactly the same but the 4.9 spreaders have had about 3/4ths of an inch cut off the ends and slotted for the spreaders.
So, for anybody "making up" a 4.9 mast you may want to consider using the Auscat spreaders rather than the "stock" 4.9 FG spreaders (if you don't want to go with the adjustable Proctor spreaders)-
