I've been enlisting the help of another developer and have asked him to use Toolset but he had an issue that I wondered if you could assist with.
He said the following:
"Speaking of Toolset, there is going to be one major problem that I can see with it right now, and that is that it does not offer you a custom field for a Post Object. In other words, you can't have a select dropdown of Riders to select when editing a Licence. It completely limits our ability to create these relationships. I personally always use Advanced Custom Fields Pro"
Does Toolset have this functionality? I noticed in a forum post form 2016 that it didn't;'t but wondered if there'd been any updates?
Alternatively does Advanced Custom Fields Pro integrate at all with Toolset? Can the two be used along side each other? That way, I can continue to use Toolset for all other functionality.
Toolset has an API filter—wpt_field_options—which can be used to dynamically populate select dropdown options.
However, it sounds like what you are aiming for is to connect "Rider" and "Licence" posts, is that correct?
Post relationships in Toolset are rather more advanced than in ACF, so I don't think handling relationships with ACF and everything else with Toolset makes much sense.
I'm not sure whether your Rider-Licence relationship would be a one-to-many or many-to-many relationship, but in any case on the edit screen for one you can add new—connected—posts of the other, or choose existing posts to connect to using a select field.
Try reading through the guide to post relationships—or point your developer there—and if you have any specific questions about applying it to your site then do let me know.