I've been creating a nurturing workflow, the idea is that this WF will be triggered each 15 minutes and will do a query then send an email, wait for 3 days, then send the second email, wait for 5 days and finally send a last email. After that a last query will check for Openers and No Openers and add those to a list.
I have 2 questions.
1. Due the WF runs every 15 minutes, but it sets recipients on a wait activity, will it queue them or will it restart the whole wf and therefore it will never do the wait activity?
2. Is there a better way to get the No Openers rather than querying the Sent emails and excluding the Openers?
With your wait activity enabled, what will occur is that when the workflow scheduler kicks off (depending on version) it will either fail or throw a warning in the workflow logs stating that the workflow is already running and will not execute again till the workflow has finished. So the only recipients that will be sent to are those from the initial run and waiting.
To your second question: I think you are going about things correctly. This is how I'd recommend querying for non-openers.