As someone who dearly detests talking to actual people, I typically prefer answering questions or getting responses via email. But, especially if you’re asking someone in senior management (they often get so many emails they don’t read them fully), sometimes it’s way more efficient just to set up a 15-minute conversation, then send out notes after.
When you send the invite, include all the questions you have in the invite body. They may respond to all your questions pretty quickly if they’re looking to avoid a meeting. If they don’t respond, meet with them, clearly tell them why you’re meeting with them and where the questions are located, go down the list with them, then send a recap afterwards with the questions and the corresponding answers saying, “Thanks for your time - below is a recap of what we discussed. Please let me know by if you have questions or comments about any of the below.
Question 1, Answer 1
Question 2, Answer 2,
Then you have the answers to all your questions all in one go, a CYA email outlining what you talked about and you’ve given a firm date by when they need to give more input should they have any questions or concerns. This is usually the approach I take with our department GMs and presidents - they don’t often have the time to go through and read each email fully, so if I can’t get everything squared away by email #2, I just throw time out on the calendar.