What is the correct bolt length?

We presented the clinical team today with 60mm bolts. They felt this was too long and asked for 55mm. 50mm, 60mm, and 70mm are easily available in the market.

**Options:**
1. 50mm, which may end up being too short if there are any issues
2. 60mm, too long, can be cut down
3. 70mm, too long, but may be useful if adding a third connector.