I say design a proper fire basket with proper distance underneath for ashes, and fill that sucker up! No need for an access door on a UDS.
Modded Brinkmann Gourmet. Basic UDS. Rescued 22.5" OTS. SJS Mini-WSM. Stubbs. B&B Oak Lump.
Cannondale 2009 F8 (for burning off all the great BBQ)