Heliman, it wouldn't be that hard to add feet ala Alan Flowers. Draw a datum through the length of the plan. Transfer that datum line to each of the formers according to their position in the model.Draw a parallel line on the plans underneath the model. Use the distance between the two lines to determine how long the legs should be. Note how Alan stabilizes his feet. Once you have added enough stringers/sheeting to locate and stabilize all of the formers then you can trim away the feet and proceed as usual.