I;m now using the delta on list items. I'm testing now on a list that has 10K items.

In my case I see that the delta request returns 1000 items max on the first query (without tokens). Querying the @odata.nextlink will return the next 1000 items.
The token (when decoded) for the first replay is '4;#3;#1;3;3779c704-bed5-42a5-be1f-005b0dee6b30;638786655338770000;378410337;#Paged=TRUE&p_ID=1000;#;#0;#'. This is the same type of tokens returned from GetListItemChangesSinceToken & other APIs.

I'll need to test how this behaves when I'm starting with a non-paged token. In case of other APIs the number of items returned per request was more limited (40 items or maybe 100 items per request).