They wouldn't be challenges if they were easy, but they are doable! You will need to get all the clay up into the wall for this to work - no extra thickness at the bottom! Some tips:
- The centered hump of clay should be relatively tall & narrow, with a flat top, before you open it. About 3" at the bottom, 2" at the top.
- Open with your thumbs bent & pointy.
- Establish a flat interior bottom before you begin pulling up
- Make sure you begin your pull with your outer fingertips right against the wheelhead.
- At the beginning of each pull, press in with your outside fingertips (for me that's my right hand) to make a little ridge of clay that you will bring up the wall.
- As soon as you begin pulling, move your outside fingertips so they are putting pressure a little bit higher than your fingertips inside the pot. This will prevent the wall from spreading outward.
- Pull as many times as you need