When not in use my drum sits on its tail. Go figure the floor space it takes up. The biggest problem
calculating chem volume is not the amt needed to do the job and keep the length of the drum
continuously wet (only about a qt), but the efficiency of the drum in maintaining critical temperature
inside. Dektol is a piece of cake. Color is more finicky. One needs enough volume to offset ambient
air temp before drifting. This is a matter of both design and conditions. To make things equal, you'd
need an efficient water jacket around the developer trough, or an attached thermoregulator with
a circulating pump for the chemistry itself. I'm not implying that your trough system is not adequate
to the task you've assigned it - but drums are way more versatile. But there is a point in size when
fiber-based paper will collapse in them.