Marge Black's suggestions on bed size

This is my 4th year of gardening on my postage-stamp sized lot. Last winter I took out all the dirt from my beds (I had originally tilled down about 8", then tilled in peatmoss and sheepshit) and tilled down another 4" and tilled in the sheepshit and peat (my soil was pure, rockhard clay). The difference in the productivity of my garden from last year is amazing! My plots are about 3' wide, they are raised, and I can reach to weed easily from both sides. I put my beds on the north-south magnetic axis because I had read in so many books that plants grew better when the beds were oriented that way.