12.1.3 - API for defined DFF segments on an asset record?

We're on 12.1.3 and we use iAssets to manage our physical inventory process, which is distributed out across our campus to what we call "inventory coordinators". They love this little self service module, and we like it too because it doesn't give all those people update access in the core Assets module via the asset workbench. But the iAssets module has a very limited scope application and use - namely to facilitate transfers of assets or to be able to search on assets. That's about it.

We want to store additional information on some of our asset records, and we're considering using a DFF for this (anyone have a recommendation on which DFF would be best to use?). The type of information we want to store is not financial, but more along the lines of how the asset is being used and by whom. And we also have an "off campus use agreement" form that employees have to fill out if they have a laptop (as an example) and it might "reside" at the employee's residence, and not at work. We want to store an expiration