Thanks for the quick replies and DPs. Many people on FT also bought GCs right away and got it to post, but some had issues and hadn't received their credits after 2+ weeks. Is there anything to lose by waiting until Motzei Shabbos to be safe? My fear was that if I buy the GCs then, they won't post until January 2018, especially with the holiday. Is it 100% that as long as the purchase is made in 2017 that they'll be credited for this year, not for 2018?