You can use a multi-arm bandit.

Spend 15 min with 20. Select the top 10.

Spend 1 Hour with top 10. Select the top 5.

Spend day with top 5. Select the top 2.

Etc.

Round robin for best performance and to prevent failure of single person

Mon - Person A

Tue - Person B

Wed - Person C

Thu - Person A

Fri - Person B ...

Round robin can work but you probably also need some weighting, it might be worth investing extra effort in one person if the stars align but still keep in contact with others until the deal is sealed.