My husband and I married in 2013. We have been battling wait times with NVC for some time. My husband had his interview in September and more information was requested. After 3 rounds of questioning his visa denied and we are now eligible to apply for an I-601 waiver. How long does it take for approval? How long does the letter need to be? What supporting documentation other than our letters need to be present? Any advise or guidance on this subject would be greatly appreciated.