I'd ask 2 questions:
1. Is there anything else I need to know before I can make a decision? If so, that's the next action.
2. One of David's questions - when will I be smarter? When do I expect to be able to make a decision? Then it'll go on my calendar on that date (or in my case, an OmniFocus due date). If that's a way off, I'll add it to my @thinking next action list, just as a reminder when I do the weekly review.