I made an adapter for a 14500 battery in a 3405 host that uses that carriage. It is just a dowel, a screw and a hole drilled almost all the way into the dowel. The 14500 slips inside the dowel and the screw makes the battery to host contact
Another member is going to be posting the way that he adapted this host for the 18650 battery.
hint - You have to cut out some of the inside "filler" of the host in the tail cap and make a diameter adapter sleeve with his mod, so the host has to have the needed extra length