Step 1Whisk together oil, honey, salt and 3 eggs, adding water gradually and whisking constantly to avoid curdling eggs. Set aside.
Step 2Stir together 2 cups pastry flour, 3 cups unbleached flour and yeast in bowl of electric mixer and make a well in the center. Add oil mixture and mix on low to medium speed with dough hook attachment until thick batter is formed, 2 to 3 minutes. Scrape down sides with a spatula. Gradually mix in remaining 1 cup pastry flour and 2 cups unbleached flour, until dough leaves sides of bowl (dough will still be somewhat sticky).
Step 3Pour out mixture on floured surface and pour a little flour on top. Knead dough in a clockwise direction, incorporating any additional flour gradually, 5 to 10 minutes. Dough is ready when it is no longer sticky, but may still be slightly moist and a little soft--something like an earlobe. Oil a bowl and turn dough over in bowl so surfaces will not dry out. Cover with a kitchen towel and place in a warm spot until dough rises and doubles in size, about 45 to 60 minutes.
Step 4Punch down dough and let rest 5 minutes. Line 2 baking sheets or 10-inch round pans with parchment paper (if using round pan, cut out a circle of paper to fit pan and affix with a little cooking spray). Cut dough in half. Using your hands, roll out each piece into a small baguette shape and coil it to make a round. Fasten end under circle with a gentle pinch. Transfer to baking sheets. Let rise again until dough doubles in size, about 45 to 60 minutes.
Step 5Beat remaining egg and brush over each challah. Sprinkle each type of seed separately over tops, starting from outside the coil into center.
Step 6Bake at 350 degrees until golden brown, about 25 to 30 minutes. Cool on a rack.
Form part of dough into 9 balls somewhat larger than pingpong balls and arrange them around inside rim of 10-inch springform pan. Use remaining dough to make 3 larger balls (about size of tennis balls) and place in center of pan. Brush with beaten egg mixed with a little water and then sprinkle a different garnish on each ball (sesame seeds, cumin seeds, caraway seeds, rosemary, oatmeal). Bake at 350 degrees until browned, about 25 minutes.