You're gonna need some place for the ash to go. I think it will fall and clog up the small holes in your drum, even potentially on the sides and that will choke your fire. That being said, I would definitely drill some holes in the drum you are using for the coals.
Most guys use expanded metal for their baskets. Also, make sure you have standoff's so the basket sits up off the floor of the UDS. Again, gives the ash a place to go. Here's a shot of the material most guys use.
Here's a good charcoal basket thread as well.