Yes, I worked in that scenario before. Here's my recommendation:
1. Zoominfo e.g. usually recommends to write data into their specific Zoominfo fields, like "ZI Job Title". Let's assume you now also connect DemandBase, you might be inclined to write their Job Title to "DB Job Title". Then you end up with three fields: "Job Title" (Marketo's native field), "ZI Job Title" and "DB Job Title". - This situation is not practical, I find. You have to decide which data provider to trust and which one field to use.
2. If you have more than one data provider you will have to create a hierarchy of trust. You can't have DB override data from ZI. So we have tried to compare match rate and data quality to create that hierarchy. I think we once decided to trust ZI first, DB second and Clearbit third. Which means: ZI can override data, DB only if field empty and Clearbit also only if field is empty aka: neither ZI nor DemandBase found a match. In order to do that, you will have to have your Order of Operations in a tight grip, i.e. you have to define exactly when to call which service.
And I don't think you really need wait times. Either the webhook comes back with a response or it doesn't. That was at least my experience, but you would need to monitor the process. I'd first try without any wait steps.
