Gardener's Block and Revisions to the Great Wall of Lettuce

By now, you know that the Great Wall of Lettuce is my raison d'etre this summer.  Aside from a few ADD meanders through sourdough bread and sunscreen, it's the only purpose I have (unless you count loading and unloading the dishwasher, the washing machine and the dryer).

But I'm stuck people.  Stuck.  Gardeners block so bad I can hardly lift the hose. 

To date we've learned through our first crop that the gallon pots are too small to support a salad-worthy lettuce crop.  So, the soil (Mel's mix of Square Foot Gardening fame) has been dumped into 2 and 5 gallon pots and refreshed with a little worm compost.  And the pots are ready for planting but I'm hung up on how to redesign the watering system. 

The problem with watering the Great Wall is channeling the runoff to reduce waste.  The original idea was that the water from the top-most pots would drain into the pots below then run into a gutter to water the peach and raspberry bushes.  This worked pretty well with the gallon pots, but it's not so neat with the larger sizes.

The problem lies in maintaining a sun-shade balance.  When the pots are stacked for drainage, the plants below don't get enough sun.  Even lettuce.  When the pots are offset, the drainage system doesn't work.  Once the drip system is in place, it gets harder to move the pots around.  So we're stuck.  Back to the drawing board.  Unless I figure this out soon, I'm going to lose another hour of life to sudoku.