I didn't believe a 10 inch top could look small, but on that photo it does!
The tip looks like it was molded by hand around a metal bar core.
(internet is being weird so if this reply shows up twice i won't be surprised)
i forgot that i put the description on the short version of the vid:
sculpted a quick tip for it out of epoxy putty on a threaded rod, shifted around some weights in the form of washers duct taped to the interior and added some tape to the exterior and interior for strength and in some cases balance.
I'll add that the sixteen washers i have duct taped to the interior i weighed at roughly one ounce each, originally i had them at near the outermost diameter but trial and error have forced me to move them closer and closer to the tip, i originally didnt think itd be a big deal to have them as a sort of weight ring but, it turns out that more weight out there means adding spin to the top as it slides down the string is way more difficult... i dunno momentum or leverage math but now that i think about it it makes sense like with gears on a mountain bike.