https://greekreporter.com/2024/06/29/sparta-treat-slaves/
More a social treatise and very limited butm may be of interest
If you like helots, Brett Deveraux covers them in his Sparta series here (https://acoup.blog/2019/08/23/collections-this-isnt-sparta-part-ii-spartan-equality/). He goes into rather more on the complexity of estimating Helot numbers and their social roles.
absolutely more detail. the overview version is a handy reference but nothing more