Diane, sorry it took me so long to answer, I'm away from home until this coming week.
Looking at the pictures I would pack your native soil amended with chicken grit and fir bark in the crevasses and then plant. I would plant them as plugs, they will take off much quicker that going through another transplant. The plugs also are smaller and easier to fit into the cracks. That way they will have soil behind them to send roots into. It is up to you on how fast you want the holes to fill in as to how many you plant in each crevase. You can plant them in any pattern that you find appealing. I like to plant just one cultivar in a spot, maybe another close by, mixing color, size and textures as I go along the wall. Let the wall dry out between waterings. You have such a wonderful variety from the co-op to make an amazing wall tapestry with. I just can't wait to see your photos after planting. Don't worry if it doesn't look filled out right away, won't be long before it looks like it's been there for many years. : )
