Also, the Web API provides a lot of meta data about tracks (more than any other entertainment platform that I am aware of), so this should be useful for both linkage designs like ours, but also when using DDPs.

Available papers from this project / using this method (so far... more to come, hopefully soon):

dl.acm.org/doi/10.1145/...

osf.io/preprints/ps...

We used the API for "real time" donations / linkage of recently listened tracks in each ESM questionnaire, no DDPs (see developer.spotify.com/documentatio...). So no experience about average download time, but API worked pretty great (unless you are interested in podcasts, which are not supported).

The paper is open access at doi.org/10/g954hw

Easy, you need to sample in some Gotye and sing along
youtu.be/riCP9x31Kuk