Yes, the two on the right in the picture are exactly what I mean. Did you fill them completely?
Before filling, I sanded the bottom of the horn and the slightly oversized top of the shank with a sanding block so they will sit flush. Then put a threaded rod in the stick coating the part of the rod going into the shank with epoxy to make it secure. I also drilled two small holes in the top of the shank to give the resin something to "hold on to". Not sure if that does any good but it made me feel more confident. I put the horn over the rod and use painters tape to hold it on and to keep any resin from seeping out when I fill from the top. I'm not 100% sure but I think it's better to not fill it all the way in one pour so the resin sets up all the way through.
I filled one of them to the top with fiber glass resin and the other with a mix of resin and saw dust being sure not to over fill. I have used a dowl and wood glue to attach the wood cap. On another stick I have also counter sinked a large wood screw from the top and inlayed a stone to fill the hole.
I attached the cap oversized then rasped, filed, and sanded to shape. I put tape around the top and bottom of the horn to protect it when shaping the wood to the same size of the horn. If the horn gets nicked just sand and polish till the scratch is gone. Before attaching the cap I sanded the top of the horn and the bottom of the cap with a sanding block so they will sit flush.
The next one I make like this I might let the threaded rod stick out the top of the horn and use that as the dowl to attach the wood cap. All this has been trial and err on my part. I made these before finding the forum so I will be following this and hopfully will learn a better way or confirm what I did was right.
