kakashi has alot of chakra now huh? o-O i remember before if he even used it he was in the hospital for a week lol also it does drain his chakra thats y his eye is either closed or covered half the time
you speak about old kakashi you act stupid character
current kakashi used 6 kamui with 3 raiki,2 light chain,2 shadow clone,earth wall(manga fact)
so kakashi with full chakra and without other jutsus can use kamui 12 times on similar sizes
kakashi has good chakra
normal sharingan doesn't drain kakashi
kakashi used it all time agaisnt kakazu,
kakahsi used it all time against obito , jinshiruki and gedo with using kamui and other jutus which i mentioned