I haven't played with the shock a lot personally, but the people I've talked to who have did not like with the shock layed down any flatter.
theisgroup is right, a captured end by itself doesn't offer much movement because the plastic hits, but if you put it on top of the cone it would. If your shock mounts on the antenna mount it would be easy to cut it down, add a cone and keep the same shock angle.

take care
john