Here is the schema we use when working with SharePoint Task List fields:
Default Fields
| Title | Text |
| StartDate | DateTime |
| DueDate | DateTime |
| PercentComplete | Number |
| AssignedTo | Assignment |
| Priority | Choice |
| Status | Choice |
| Body | TEXTAREA |
Text Fields
| Text1 | Text |
| Text2 | Text |
| ... | ... |
| Text30 | Text |
Number Fields
| Number1 | Number |
| Number2 | Number |
| ... | ... |
| Number20 | Number |
Cost Fields
| Cost1 | Number |
| Cost2 | Number |
| ... | ... |
| Cost10 | Number |
Date Fields
| Date1 | DateTime |
| Date2 | DateTime |
| ... | ... |
| Date10 | DateTime |
Special Fields