Looks very functional. What provisions have you made for ventilation? Is the water heater gas or electric? Gas may be a consideration in how you put the enlarger table in as you have to get in to relight the fire on occasion. With electric you could hang some cabinets in the free space over it. Also look into getting some shelves or ready made cabinets hung over the trays for storage. I put those wire shelves over my sink, three levels, and I still run out of room.