Really great idea!
It works fine for pouring soil-less mix into insert trays and plug trays for seed starting, or 4" pots for potting-up! The spill-over goes right back into the wheelbarrow, which makes filling corner cells and edge cells much easier.
A board-on-a-barrow is also good for chopping up fruit-stand-rejects for the compost heap, with a cleaver.
Two wheelbarrows side-by-side make it much easier to screen bark or compost or chipped wood. The only time I have to bend over is to pick up "rejects" that I flipped off the screens onto a tarp spread under the wheelbarrows.
