Hugels dont need to be 7ft high, the thing Ive found is to remember that you are trying to recreate a rain forest floor and its many layers of compost. I have had great success in a semi arid environ with shovel dug trenches on contour filled with timber and covered in soil then a quick compost layer of lucerne and poo on top.
As to the drying out of the pile, Ive found that as the mound is being made a lot of effort must be put into eliminating air gaps in and around the timber and the soil must cover all wood to prevent moisture losses.
The other great thing is the north and south sides of the Hugel are two different climate zones, one side grows sweet potato and the other side daisys.