Door ferrules or ferrells what ever

[Michael C Henry]

I'm intent on getting my soft top and side curtains installed. I have an 84 Everett Morrison 427 SC replica, FIBERGLASS. I bought the top and side curtains from EM when they sold kits and parts from Florida (2001). I'm trying to get as much of the odd parts before the deed. The ferrules that came with from EM are threaded with nuts, polished round heads about 3/16" tall with square sides, that sit above door surface. They kind of look as if they were a stack of same size washers. Then I look at original aluminum cars and the ferrules they have are just slightly raised higher than the door surface with out side edges tapering to blend with the door surface. You may actually lay your arm on them. I now know that the original aluminum cars had pieces of pipe welded into the door to accept the smooth body ferrules, secured with a external snap ring on each ferrule. The original cars have three ferrules per door. The fiberglass replica ferrules have a threaded body with a nut that holds the ferrule to the fiberglass door top surface. Why did EM make their ferrules with the thick heads like this and why only two ferrules for each door? Did they have problems with the smooth slight original style head cracking from stress?
From what I've seen EM made the side curtain with only two down shafts so you could lay your arm across the door between the ferrules when side curtain was not being used. And the squarish heads were easier to make. I'm thinking I want three down shafts per side curtain and the ferrules should be the slight headed ferrules but with the threaded body and nut That outwardly resemble the originals. any response?