After making quite a few rough models the team decided on the strongest versions and went on to make more realized versions of the rough sketches. We used thermoplastic, and torsion springs. We also considered the need to keep the parts that touch the top of the hand non abrasive.
It seems to work well. The finger is extended naturally, and there is still the ability to bend at the second joint. The brace on the palm gives a good deal of leverage, especially when bending the finger. We kept the splint pretty stream lined, you can put the hand in a pocket, but we still need to consider making that easier. The springs work very well, but we also need to make a better interface for them to fit into the splint and hold. The thermoplastic works really well and is very form-able, however it is not perfect. As you work on one part another runs the risk of being deformed. Casting and printing both seem to have potential, but there are limitations to both. The main ones being the resources and know-how needed to do either.